imperil
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C1 verb /ɪmˈpɛrɪl/

imperil

poner en peligro
Meaning
To put in danger or at risk.
Example
Reckless driving can imperil the lives of others.
La conducción imprudente puede poner en peligro la vida de otros.
C1 noun /ˈɪŋ.krə.mənt/

Increment

aumento
Meaning
an increase or addition, especially one of a series on a fixed scale; a regular increase in salary
Example
He received an annual increment of five percent in his salary this year.
Recibió un aumento anual del cinco por ciento en su salario este año.
C1 adjective /ɪnˈfriːkwənt/

infrequent

poco frecuente
Meaning
Happening rarely or not often.
Example
He made infrequent visits to his hometown after moving abroad.
Él hacía visitas poco frecuentes a su ciudad natal después de mudarse al extranjero.
C1 noun ˌɪnˈsaɪtfʊlnɪs

insightfulness

perspicacia, capacidad de análisis
Meaning
The capacity to gain an accurate and deep intuitive understanding of a person or thing.
Example
His insightfulness helped solve the complex problem.
Su perspicacia ayudó a resolver el problema complejo.
C1 verb /ɪnˈterəˌɡeɪt/

interrogate

interrogar
Meaning
to ask someone questions in a thorough and formal way; to question intensively
Example
The police interrogated the suspect for hours.
La policía interrogó al sospechoso durante horas.
C1 noun /ˌɪnkənˈsɪstənsi/

inconsistency

inconsistencia
Meaning
The quality of being contradictory, irregular, or not staying the same.
Example
There is an inconsistency between his words and actions.
Hay una inconsistencia entre sus palabras y acciones.
C1 adjective /ˌɪn.səˈbɔːr.dɪ.nət/

insubordinate

insubordinado
Meaning
Defiant of authority; disobedient to orders.
Example
The insubordinate employee refused to follow the manager's instructions.
El empleado insubordinado se negó a seguir las instrucciones del gerente.
C1 adjective /ɪnˈstrʌktɪv/

instructive

instructivo
Meaning
useful and informative; providing knowledge or instruction
Example
The lecture was highly instructive and engaging.
La conferencia fue muy instructiva y atractiva.
C1 noun /ˌɪn.səˌbɔːr.dɪˈneɪ.ʃən/

insubordination

insubordinación
Meaning
Defiance of authority; refusal to obey orders.
Example
The soldier was punished for insubordination during the mission.
El soldado fue castigado por insubordinación durante la misión.
C1 adjective /ɪnˈflæməbəl/

Inflammable

inflamable; combustible
Meaning
easily set on fire; flammable; combustible
Example
The inflammable material caught fire quickly.
El material inflamable se prendió rápidamente.
C1 adjective /ɪmˈpɛndɪŋ/

impending

inminente
Meaning
about to happen soon, usually something unpleasant or threatening
Example
The villagers were worried about the impending flood.
Los aldeanos estaban preocupados por la inundación inminente.
C1 verb /ɪnˈfleɪm/

inflame

inflamar
Meaning
to arouse strong feelings or provoke anger; to cause inflammation in the body
Example
The politician's remarks served to inflame public opinion.
Las declaraciones del político sirvieron para inflamar la opinión pública.
C1 verb /ɪmˈplɔːr/

implore

implorar
Meaning
To beg someone earnestly or desperately to do something.
Example
She implored him to stay with her.
Ella le imploró que se quedara con ella.
C1 noun /ɪnˈfɜː.mə.ti/

Infirmity

debilidad; enfermedad; fraqueza
Meaning
physical or mental weakness; a disease or ailment; frailty
Example
Despite his advanced age and various infirmities, he remained mentally sharp and alert.
A pesar de su avanzada edad y varias enfermedades, se mantuvo mentalmente agudo y alerta.
C1 adjective /ˌɪndɪˈstrʌktəbl/

indestructible

indestructible
Meaning
Impossible to destroy or break.
Example
The superhero's shield was said to be indestructible.
Se dijo que el escudo del superhéroe era indestructible.
C1 adjective /ɪˈmuː.və.bəl/

immovable

inmóvil
Meaning
Not able to be moved; fixed in position.
Example
Immovable barriers prevent change.
Las barreras inmóviles impiden el cambio.
C1 noun ˌɪndɪˈspensəbl səˈpɔːrt

indispensable support

apoyo indispensable
Meaning
Essential assistance that cannot be done without; absolutely necessary help.
Example
Volunteers provide indispensable support to communities.
Los voluntarios proporcionan apoyo indispensable a las comunidades.
C1 adjective /ɪnˈsteɪbəl/

instable

inestable
Meaning
not stable; liable to change, collapse, or fail; lacking firmness or reliability
Example
The instable political situation worried foreign investors.
La situación política inestable preocupó a los inversores extranjeros.
C1 adjective /ɪnˈflæməˌtɔːri/

inflammatory

felicidad
Meaning
causing inflammation in the body; arousing anger, hostility, or strong emotion
Example
His inflammatory speech triggered protests across the city.
No pudo esconder su felicidad cuando recibió el premio.
C1 adjective /ɪˈlɪsɪt/

illicit

ilícito
Meaning
Forbidden by law, rules, or custom.
Example
The police shut down the illicit drug operation.
La policía cerró la operación de drogas ilícitas.
C1 adjective ˌɪn.trəˈspek.tɪv

introspective

introspectivo
Meaning
Characterized by or given to introspection; examining one's own thoughts and feelings.
Example
Writers tend to be highly introspective individuals.
Los escritores tienden a ser individuos altamente introspectivos.
C1 verb /ɪɡˈnaɪt/

ignite

encender
Meaning
To catch fire or cause to catch fire; to start or arouse.
Example
The sparks ignited the dry leaves in seconds.
Las chispas encendieron las hojas secas en segundos.
C1 noun /ˌɪntərˈdʒɛkʃən/

interjection

interjección
Meaning
a word or phrase used to express sudden emotion or reaction, often standing alone
Example
Words like 'wow' and 'ouch' are common interjections in English.
Palabras como 'wow' y 'ouch' son interjecciones comunes en inglés.
C1 verb /ɪnˈkɜːr/

incur

incurrir
Meaning
To bring upon oneself something undesirable, usually as a result of actions.
Example
He incurred a fine for parking in the wrong place.
Él incurrió en una multa por aparcar en el lugar equivocado.
C1 noun /aɪˈtɪnərɛri/

itinerary

itinerario
Meaning
A planned route or schedule of a journey or trip.
Example
The travel agent gave us a detailed itinerary for our vacation.
El agente de viajes nos dio un itinerario detallado para nuestras vacaciones.
C1 adjective /ˌɪn.səbˈstæn.ʃəl/

insubstantial

insustancial
Meaning
Lacking strength, substance, or solidity.
Example
The evidence provided was insubstantial and unconvincing.
La evidencia proporcionada fue insustancial y poco convincente.
C1 adjective /ɪˈnɔːɡjərəl/

Inaugural

inaugural
Meaning
marking the beginning of something; first; opening
Example
The president delivered his inaugural speech.
El presidente dio su discurso inaugural.
C1 adjective /ˌɪndɪˈskraɪbəbəl/

Indescribable

indescriptible
Meaning
impossible to describe or express in words; beyond description
Example
The beauty of the sunset was indescribable.
La belleza del atardecer era indescriptible.
C1 adjective /ɪmˈpæsɪv/

impassive

impasible
Meaning
Not showing or feeling emotion; expressionless.
Example
Despite the shocking news, she remained impassive.
A pesar de las noticias impactantes, ella permaneció impasible.
C1 adjective /ɪnˈkɒŋɡruəs/

incongruous

incongruente
Meaning
Not fitting in with or suitable for the surroundings.
Example
His jokes were incongruous during the serious meeting.
Sus chistes fueron incongruentes durante la reunión seria.
C1 verb /ɪnˈfrɪndʒ/

infringe

infringir
Meaning
To actively break the terms of a law, agreement, or right.
Example
Copying this software without permission will infringe copyright laws.
Copiar este software sin permiso infringirá las leyes de derechos de autor.
C1 noun /ˈɪnflʌks/

influx

afluencia
Meaning
A large arrival or flow of people or things.
Example
The city experienced an influx of tourists during the festival.
La ciudad experimentó una afluencia de turistas durante el festival.
C1 noun /ˌɪntərˈmɪʃən/

intermission

intermedio
Meaning
A pause or break, especially during a performance or event.
Example
The play had a twenty-minute intermission.
La obra tuvo un intermedio de veinte minutos.
C1 adjective /ɪmˈpɜːrviəs/

impervious

impermeable
Meaning
Not allowing fluid to pass through; unable to be affected by something.
Example
The jacket is impervious to rain.
La chaqueta es impermeable a la lluvia.
C1 adjective ɪnˈtrɪn.zɪk

intrinsic

intrínseco, esencial, natural
Meaning
Belonging naturally; essential. Existing as a natural or basic part of something.
Example
Creativity is an intrinsic quality of a great artist.
La creatividad es una cualidad intrínseca de un gran artista.
C1 noun /ɪˌluːmɪˈneɪʃən/

illumination

iluminación
Meaning
the act of lighting something or making something clear
Example
The street was filled with bright illumination from the lamps.
La calle estaba llena de una iluminacion brillante proveniente de las lamparas.
C1 noun ˌɪnfɛsˈteɪʃən

infestation

infestación, gran número de insectos o animales en un lugar
Meaning
The presence of an unusually large number of insects or animals in a place, causing damage or disease.
Example
The infestation of ants in the kitchen led to immediate pest control measures.
La infestación de hormigas en la cocina llevó a medidas inmediatas de control de plagas.
C1 adjective /ˌɪnsɪˈdɛntəl/

incidental

incidental
Meaning
happening as a minor part or in connection with something else
Example
Incidental expenses like snacks and tips were included in the bill.
Gastos incidentales como bocadillos y propinas fueron incluidos en la factura.
C1 noun /ˈɪntrɪkəsi/

intricacy

complejidad
Meaning
the quality of being very detailed or complicated
Example
The intricacy of the design impressed everyone.
La complejidad del diseño impresionó a todos.
C1 verb /ɪnˈhɪbɪt/

inhibit

inhibir
Meaning
to prevent or restrain someone or something from acting freely; to hinder
Example
Fear can inhibit personal growth.
El miedo puede inhibir el crecimiento personal.
C1 adjective /ɪnˈdʌktɪv/

inductive

inductivo
Meaning
characterized by the inference of general laws from particular instances; reasoning from specific cases to general principles
Example
The scientist used inductive reasoning to form a hypothesis.
El científico usó razonamiento inductivo para formular una hipótesis.
C1 verb /ˈɪmprəvaɪz/

improvise

improvisar
Meaning
To create or perform something spontaneously without preparation.
Example
The actor had to improvise his lines when he forgot the script.
El actor tuvo que improvisar sus líneas cuando olvidó el guion.
C1 noun /ɪnˈdʒʌŋkʃən/

injunction

orden judicial
Meaning
A judicial order restraining a person from an action or compelling a certain act.
Example
The court issued an injunction to stop the company from polluting the river.
El tribunal emitió una orden judicial para evitar que la empresa contaminara el río.
C1 noun /ˌɪnkɑːrˈneɪʃən/

incarnation

encarnación
Meaning
the embodiment of a deity, spirit, or quality in a physical form
Example
The monk was considered the incarnation of compassion.
El monje fue considerado la encarnación de la compasión.
C1 adjective /ɪnˈtændʒəbl/

intangible

intangible
Meaning
Unable to be touched or grasped; not having a physical presence.
Example
Trust is an intangible quality in relationships.
La confianza es una cualidad intangible en las relaciones.
C1 adjective /ˌɪntərˈtʃeɪndʒəbl/

interchangeable

intercambiable
Meaning
able to be exchanged with each other without difference or loss of function
Example
These machine parts are interchangeable, so they can be replaced easily.
Estas piezas de la máquina son intercambiables, por lo que se pueden reemplazar fácilmente.
C1 noun /ˌɪnækˈtɪvɪti/

inactivity

inactividad
Meaning
the state of not being active physically or mentally; lack of action
Example
Prolonged inactivity can negatively affect both physical and mental health.
La inactividad prolongada puede afectar negativamente la salud física y mental.
C1 adjective /ˈɪrɪtəbl/

irritable

irritable
Meaning
easily annoyed or made angry
Example
She became irritable after working long hours without rest.
Ella se volvió irritable después de trabajar muchas horas sin descanso.
C1 noun /ˌɪnkəmˌpætəˈbɪlɪti/

incompatibility

incompatibilidad
Meaning
the state of being unable to exist or work together harmoniously; lack of compatibility
Example
The project failed because of incompatibility between the two software systems.
El proyecto fracasó por la incompatibilidad entre los dos sistemas de software.
C1 noun /ˈɪnstɪˌɡeɪtər/

instigator

instigador
Meaning
A person who brings about or initiates something, usually something bad.
Example
The police identified him as the instigator of the violence.
La policía lo identificó como el instigador de la violencia.
C1 noun /ɪnˈkɒmpɪtəns/

incompetence

incompetencia
Meaning
Lack of ability, skill, or effectiveness in doing something.
Example
The project failed due to the manager’s incompetence.
El proyecto fracasó debido a la incompetencia del gerente.
C1 adjective /ˌɪnkəʊˈhɪərənt/

incoherent

incoherente
Meaning
Not clear or easy to understand; lacking logical connection.
Example
His explanation was so incoherent that nobody could follow it.
Su explicación era tan incoherente que nadie pudo seguirla.
C1 verb /ɪmˈploʊd/

implode

implosionar
Meaning
To collapse or burst inward violently.
Example
The old building imploded during the demolition.
El viejo edificio implosionó durante la demolición.
C1 noun /ˌɪnsəˈfɪʃənsi/

insufficiency

insuficiencia
Meaning
The state of not being enough or not being adequate.
Example
The project failed due to the insufficiency of funds.
El proyecto falló debido a la insuficiencia de fondos.
C1 verb /ˈɪnsjuleɪt/

insulate

aislar
Meaning
To protect something by covering it, especially to prevent heat, sound, or electricity from escaping or entering.
Example
The house was insulated to reduce heating costs.
La casa fue aislada para reducir los costos de calefacción.
C1 noun ɪˌræʃ.ənˈæl.ɪ.ti

irrationality

irracionalidad, falta de lógica, irrazonabilidad
Meaning
The quality of being illogical or unreasonable; lack of rational thought.
Example
His decision was driven by complete irrationality.
Su decisión fue impulsada por una irracionalidad completa.
C1 verb /ɪnˈfleɪt/

inflate

inflar
Meaning
to fill with air or gas so it expands; to increase excessively or artificially
Example
The mechanic inflated the tire to the correct pressure.
El mecánico infló el neumático a la presión correcta.
C1 adjective ˌɪn.tə.dʒen.əˈreɪ.ʃən.əl

intergenerational

intergeneracional, entre diferentes generaciones de una familia
Meaning
Existing or occurring between different generations of a family.
Example
Intergenerational wisdom ensures cultural continuity.
La sabiduría intergeneracional asegura la continuidad cultural.
C1 adjective /ɪnˈvɑːlənˌtɛri/

involuntary

involuntario
Meaning
done without will or conscious control
Example
He gave an involuntary shiver when he heard the loud noise.
Él dio un escalofrío involuntario cuando escuchó el ruido fuerte.
C1 noun /ɪnˈdaɪtmənt/

indictment

acusación formal
Meaning
a formal charge or accusation of a serious crime
Example
The indictment accused the company of multiple violations.
La acusación formal acusó a la empresa de múltiples violaciones.
C1 noun /ɪmˈpɛd.ɪ.mənt/

impediment

obstáculo
Meaning
A hindrance or obstruction in doing something; something that prevents progress.
Example
Lack of funds is a major impediment to the project.
La falta de fondos es un gran obstáculo para el proyecto.
C1 verb /ˌɪntəˈsɛkt/

intersect

intersectar
Meaning
to cross or pass through each other
Example
The two roads intersect at the city center.
Los dos caminos se intersectan en el centro de la ciudad.
C1 noun /ˌɪmɔːrˈtæləti/

immortality

inmortalidad
Meaning
the state of living forever; eternal life or lasting fame beyond death
Example
Many ancient cultures believed that heroes could achieve immortality through great deeds.
Muchas culturas antiguas creían que los héroes podían alcanzar la inmortalidad mediante grandes hazañas.
C1 adjective /ɪnˈflɛksəbl/

inflexible

inflexible
Meaning
Not able to bend or change; unwilling to change ideas or behavior.
Example
His inflexible attitude made negotiations difficult.
Su actitud inflexible dificultó las negociaciones.
C1 adjective /ɪnˈvɪnsəbl/

invincible

invencible
Meaning
too powerful to be defeated or overcome
Example
The team seemed invincible after winning ten matches in a row.
El equipo parecía invencible después de ganar diez partidos consecutivos.
C1 verb /ɪnˈvɪɡ.ər.eɪt/

invigorate

revitalizar
Meaning
To give strength or energy to someone or something.
Example
A morning walk can invigorate both body and mind.
Una caminata matutina puede revitalizar tanto el cuerpo como la mente.
C1 noun /ɪnˈækjʊrəsi/

inaccuracy

inexactitud
Meaning
lack of accuracy or precision; an incorrect or wrong detail
Example
The report contained several factual inaccuracies.
El informe contenía varias inexactitudes.
C1 adjective /ˌɪməˈtɪəriəl/

immaterial

inmaterial
Meaning
Not important or relevant; lacking physical substance.
Example
The judge ruled that the argument was immaterial to the case.
El juez falló que el argumento no era relevante para el caso.
C1 adjective /ɪmˈpɛn.ɪ.trə.bəl/

impenetrable

impenetrable
Meaning
Impossible to pass through or enter; impossible to understand.
Example
The dense forest was nearly impenetrable.
El bosque denso era casi impenetrable.
C1 noun /ɪnˈdjuːsmənt/

inducement

inducido
Meaning
something that persuades or encourages someone to do something
Example
The company offered a bonus as an inducement to employees.
La empresa ofreció un bono como incentivo para los empleados.
C1 verb /ɪnˈkɑːrsəreɪt/

incarcerate

encarcelar
Meaning
to imprison or confine someone
Example
The authorities incarcerated the criminal after the trial.
Las autoridades encarcelaron al criminal después del juicio.
C1 adjective /ɪnˈhjuːmən/

Inhuman

inhumano
Meaning
lacking human qualities; cruel; brutal; savage
Example
The dictator's inhuman treatment of prisoners shocked the international community.
El trato inhumano del dictador hacia los prisioneros sorprendió a la comunidad internacional.
C1 verb /ɪnˈstɪl/

instill

instruir
Meaning
to gradually but firmly establish an idea, attitude, or habit in someone's mind
Example
Parents try to instill good values in their children.
Los padres intentan inculcar buenos valores en sus hijos.
C1 adjective /ɪˈlʌstriəs/

illustrious

ilustre
Meaning
Well known, respected, and admired for past achievements.
Example
She had an illustrious career in medicine.
Tuvo una carrera ilustre en la medicina.
C1 verb /ˌɪntərˈsɛpt/

intercept

interceptar
Meaning
to stop, catch, or seize something on its way from one place to another
Example
The police intercepted the stolen car before it crossed the border.
La policía interceptó el coche robado antes de que cruzara la frontera.
C1 adjective /ˌɪnsərˈmaʊntəbl/

insurmountable

insuperable
Meaning
Too great to be overcome.
Example
The explorers faced insurmountable odds in the desert.
Los exploradores enfrentaron obstáculos insuperables en el desierto.
C1 verb /aɪˈdiː.ə.laɪz/

idealize

idealizar
Meaning
To regard or represent something as perfect or better than it really is.
Example
Children often idealize their parents.
Los niños a menudo idealizan a sus padres.
C1 adjective /ɪnˈvɜːs/

Inverse

inverso; opuesto
Meaning
opposite in order, nature, or effect; reversed
Example
There is an inverse relationship between price and demand.
Existe una relación inversa entre el precio y la demanda.
C1 adjective /ˌɪnɑːrˈtɪkjʊlət/

inarticulate

inarticulado
Meaning
Unable to express oneself clearly or effectively in speech or writing.
Example
She became inarticulate with emotion during the speech.
Ella se volvió inarticulada con emoción durante el discurso.
C1 adjective /ɪˈnænɪmət/

inanimate

objeto inanimado
Meaning
not alive, especially not in the manner of animals and humans; lifeless
Example
The museum was full of inanimate objects from ancient times.
El museo estaba lleno de objetos inanimados de tiempos antiguos.
C1 adjective /ˈɪnbɔːrn/

Inborn

innato; congénito; inherente
Meaning
existing from birth; natural; inherent
Example
She has an inborn talent for music.
Ella tiene un talento innato para la música.
C1 adjective /ˌɪnkənˈsɪdərət/

inconsiderate

desconsiderado
Meaning
Thoughtless; showing a lack of concern for others.
Example
It was inconsiderate of him to play loud music late at night.
Fue desconsiderado de su parte poner música alta tarde en la noche.
C1 adjective /ˌaɪ.di.əˈlɒdʒ.ɪ.kəl/

ideological

ideológico
Meaning
Relating to or based on a system of ideas or beliefs.
Example
The two parties are divided by deep ideological differences.
Las dos partes están divididas por profundas diferencias ideológicas.
C1 adjective /ɪnˈdɪɡnənt/

indignant

indignado
Meaning
Feeling or showing anger at something considered unfair or unjust.
Example
She was indignant when accused of cheating.
Ella estaba indignada cuando la acusaron de hacer trampa.
C1 verb /ɪˈluːmɪneɪt/

illuminate

iluminar
Meaning
To light up or make something clearer.
Example
Streetlights illuminate the road at night.
Las farolas iluminan la carretera de noche.
C1 adjective /ɪnˈsɒlvənt/

insolvent

insolvente
Meaning
unable to pay debts owed
Example
The insolvent firm could not meet its financial obligations.
La empresa insolvente no pudo cumplir con sus obligaciones financieras.
C1 verb /ˈɪmplɪˌkeɪt/

implicate

implicar
Meaning
To show someone’s involvement in a crime or wrongdoing.
Example
The evidence implicated several officials in the scandal.
La evidencia implicó a varios funcionarios en el escándalo.
C1 adjective /ɪˈmækjələt/

immaculate

inmaculado
Meaning
perfectly clean, neat, or free from flaws
Example
Her room was immaculate, with everything in its place.
Su habitación estaba inmaculada, con todo en su lugar.
C1 noun ˌɪn.tuˈɪʃ.ən

intuition

intuición
Meaning
The ability to understand something immediately, without the need for conscious reasoning.
Example
Her intuition told her something was wrong.
Su intuición le dijo que algo estaba mal.
C1 adjective /ɪmˈpɑːrʃəl/

Impartial

imparcial; neutral
Meaning
treating all sides fairly; unbiased; neutral
Example
A good judge must remain impartial throughout the trial.
Un buen juez debe mantenerse imparcial durante todo el juicio.
C1 adjective /ɪmˈpɛtʃ.u.əs/

impetuous

impulsivo
Meaning
Acting or done quickly and without thought or care; impulsive.
Example
His impetuous decision led to unexpected consequences.
Su decisión impulsiva condujo a consecuencias inesperadas.
C1 adjective /ˌɪnkənˈkluːsɪv/

inconclusive

inconcluso
Meaning
Not leading to a definite result or decision.
Example
The investigation remained inconclusive due to a lack of evidence.
La investigación permaneció inconclusa debido a la falta de evidencia.
C1 adjective /ˈɪnsələnt/

insolent

insolente, arrogante
Meaning
showing a rude and arrogant lack of respect
Example
The insolent student refused to follow the teacher's instructions.
El estudiante insolente se negó a seguir las instrucciones del maestro.
C1 verb /ˈɪnkjʊˌbeɪt/

incubate

incubar
Meaning
to keep eggs, cells, or organisms at the right conditions for development
Example
The hen will incubate the eggs until they hatch.
La gallina incubará los huevos hasta que eclosionen.
C1 noun /ˌɪməˈtjʊərəti/

immaturity

inmadurez
Meaning
the state of not being fully developed emotionally, mentally, or physically; lack of maturity
Example
His immaturity made it difficult for him to handle responsibility.
Su inmadurez le dificultó manejar la responsabilidad.
C1 noun /ˌɪndɪɡˈneɪʃən/

indignation

indignación
Meaning
Strong displeasure or anger caused by something unjust, offensive, or insulting.
Example
Public indignation grew after the unfair verdict.
La indignación pública creció después del veredicto injusto.
C1 adjective ɪnˈkʌm.bənt

incumbent

obligatorio
Meaning
necessary for (someone) as a duty or responsibility.
Example
It is incumbent upon all citizens to obey the law.
Es obligatorio para todos los ciudadanos obedecer la ley.
C1 adjective /ˌɪndɪˈsaɪsɪv/

Indecisive

indeciso
Meaning
unable to make decisions quickly; hesitant; wavering
Example
She was indecisive about which university to attend.
Ella estaba indecisa sobre qué universidad asistir.
C1 adjective /ɪnˈsʌf.ər.ə.bəl/

insufferable

insoportable
Meaning
Too extreme to bear; intolerable.
Example
The heat during the summer was insufferable.
El calor durante el verano fue insoportable.
C1 verb /ɪmˈpɛər/

impair

deteriorar
Meaning
to weaken or damage something, especially a function or ability
Example
Smoking can impair your lung capacity.
Fumar puede dañar tu capacidad pulmonar.
C1 noun /ɪnˈfjuːʒən/

infusion

infusión
Meaning
the act of introducing something into another; a drink made by steeping leaves or herbs in liquid
Example
She prepared a calming infusion of chamomile tea.
Ella preparó una infusión calmante de té de manzanilla.
C1 adjective ɪnˈdel.ə.bəl

indelible

indeleble
Meaning
Making marks that cannot be removed; impossible to forget or remove.
Example
Her speech left an indelible mark on the audience.
Su discurso dejó una marca indeleble en la audiencia.
C1 noun /ɪˈmɜː.ʃən/

immersion

inmersión
Meaning
Complete engagement in an environment or experience.
Example
Immersion in VR games makes users feel like they are inside the virtual world.
La inmersión en juegos de VR hace que los usuarios sientan como si estuvieran dentro del mundo virtual.
C1 adjective /ɪnˈtrɛpɪd/

intrepid

intrépido
Meaning
fearless and adventurous, often used humorously
Example
The intrepid traveler explored the jungle alone.
El intrépido viajero exploró la jungla solo.
C1 adjective /ɪˈmjuː.tə.bəl/

immutable

inmutable
Meaning
Unchangeable, permanent, or fixed
Example
The laws of physics are considered immutable.
Las leyes de la física son consideradas inmutables.
C1 adjective /ɪnˈdʌldʒənt/

indulgent

indulgente
Meaning
Having a tendency to be overly generous or lenient with someone.
Example
The indulgent mother allowed her child to stay up late.
La madre indulgente permitió que su hijo se quedara despierto hasta tarde.
C1 adjective ˌɪn.təˈstel.ər

interstellar

entre las estrellas, interestelar, cósmico
Meaning
Occurring or situated between stars.
Example
Scientists study interstellar travel possibilities.
Los científicos estudian las posibilidades de viajes interestelares.
C1 noun /ˈɪŋklɪŋ/

inkling

presentimiento
Meaning
A slight idea, hint, or suspicion about something.
Example
She had an inkling that he was planning a surprise.
Ella tenía una ligera sospecha de que él estaba planeando una sorpresa.
C1 verb /ɪnˈtɒksɪkeɪt/

intoxicate

felicidad
Meaning
to make someone lose control of their faculties or behavior due to alcohol or drugs
Example
The strong drink quickly intoxicated him.
No pudo esconder su felicidad cuando recibió el premio.
C1 adjective /ɪˈrɛvəkəbl/

irrevocable

irreversible
Meaning
Not able to be revoked, changed, or undone.
Example
She made an irrevocable decision to leave the company.
Ella tomó una decisión irreversible de dejar la empresa.
C1 noun ɪnˈsɛpʃən

inception

inicio
Meaning
The establishment or starting point of an institution or activity.
Example
The inception of the company marked a new era in the industry.
La incepción de la empresa marcó una nueva era en la industria.
C1 noun /ɪmˈpɛdɪmənt/

impediments

obstáculos
Meaning
A hindrance or obstruction in doing something; things that prevent progress or achievement.
Example
Economic impediments often hinder social development.
Los obstáculos económicos a menudo dificultan el desarrollo social.
C1 noun /ˌɪnɪkˈspɪəriəns/

inexperience

inexperiencia
Meaning
Lack of knowledge or skill in a particular activity or field.
Example
His inexperience in handling negotiations was evident.
Su inexperiencia en las negociaciones era evidente.
C1 noun ɪnˌten.sɪ.fɪˈkeɪ.ʃən

intensification

intensificación
Meaning
The process of becoming or making something more intense or extreme.
Example
The intensification of climate change requires urgent action.
La intensificación del cambio climático requiere una acción urgente.
C1 adverb /ɪnˈvɜːrs.li/

Inversely

inversamente; en sentido opuesto
Meaning
in a way that is opposite or contrary; in reverse order or manner
Example
The price of goods is inversely related to their availability in the market.
El precio de los productos está inversamente relacionado con su disponibilidad en el mercado.
C1 adjective /ɪnˈveə.ri.ə.bəl/

Invariable

invariable; constante; siempre igual
Meaning
never changing; constant; always the same
Example
His invariable routine includes morning exercise and coffee.
Su rutina invariable incluye ejercicio por la mañana y café.
C1 verb /ɪˈmɔːrtəlaɪz/

immortalize

inmortalizar
Meaning
to preserve the memory of someone or something forever
Example
The statue was built to immortalize the hero’s sacrifice.
La estatua fue construida para inmortalizar el sacrificio del héroe.
C1 adjective ɪnˈdʒiː.ni.əs

ingenious

ingenioso
Meaning
Showing inventiveness and skill; clever, original, and inventive.
Example
His ingenious ideas transformed modern physics.
Sus ideas ingeniosas transformaron la física moderna.
C1 noun /ɪnˈsɜːrdʒənt/

insurgent

insurgente
Meaning
A person who rises in revolt against authority or government.
Example
The army arrested several insurgents after the attack.
El ejército arrestó a varios insurgentes después del ataque.
C1 adjective /ˌɪrɪˈspɛktɪv/

Irrespective

irrespetuoso; sin tener en cuenta
Meaning
without taking something into account; regardless of
Example
All students will be treated equally, irrespective of their background.
Todos los estudiantes serán tratados por igual, independientemente de su origen.
C1 noun /ˌɪnflɛksɪˈbɪlɪti/

inflexibility

inflexibilidad
Meaning
the quality of being rigid or unwilling to change; lack of adaptability
Example
The inflexibility of the rules caused unnecessary delays.
La inflexibilidad de las reglas causó retrasos innecesarios.