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B1 adjective /əˈrɪdʒ.ɪ.nəl/

Original

original; primario; auténtico
Meaning
first; fundamental; primary; authentic
Example
This is the original document, not a copy.
Este es el documento original, no una copia.
C1 adjective /ˌɒbsəˈliːt/

obsolete

obsoleto
Meaning
No longer in use or out of date.
Example
Floppy disks are now completely obsolete.
Los disquetes ahora están completamente obsoletos.
C1 noun /ˈɒf.sprɪŋ/

offspring

descendencia
Meaning
a person's child or children; an animal's young
Example
The bird carefully fed its offspring.
El pájaro alimentó cuidadosamente a su descendencia.
C1 noun /ˈɑːdəsi/

odyssey

viaje largo
Meaning
a long, adventurous journey; a series of experiences
Example
Her career has been an odyssey of challenges and achievements.
Su carrera ha sido una odisea de desafíos y logros.
C2 adjective /ˈɔːrəˌtʌnd/

orotund

voz grave y clara
Meaning
full, rich, and clear in sound; pompous in style
Example
The actor's orotund voice filled the theater.
La voz grave del actor llenó el teatro.
B1 adverb /əˈkeɪʒənəli/

Occasionally

ocasionalmente; de vez en cuando;
Meaning
sometimes; from time to time; not regularly
Example
I occasionally visit my grandmother on weekends.
A veces visito a mi abuela los fines de semana.
C2 noun /ˈoʊ.vər.let/

Overlet

colchón adicional
Meaning
a thin mattress or pad placed over a bed for additional comfort
Example
The overlet makes the bed more comfortable to sleep on.
El overlet hace la cama más cómoda para dormir.
A2 noun /ˈɒbdʒɪkt/

object

objeto
Meaning
a thing that can be seen and touched
Example
The table is an object in the room.
La mesa es un objeto en la habitación.
C2 noun /ˌɒpəˈrɛtə/

operetta

ópera ligera
Meaning
a short opera with light and humorous themes
Example
The theater staged a famous operetta by Gilbert and Sullivan.
El teatro presentó una famosa opereta de Gilbert y Sullivan.
C1 noun /ˈɔr.i.ənt/

Orient

Oriente, especialmente los países de Asia oriental
Meaning
the East, especially countries of eastern Asia; to determine one's position or direction
Example
Many spices come from the Orient.
Muchas especias vienen del Oriente.
C1 adjective /ˌɑːpərˈtuːn/

opportune

momento oportuno
Meaning
Happening at a suitable or convenient time.
Example
She arrived at an opportune moment to help.
Llegó en un momento oportuno para ayudar.
C1 noun /ˈoʊ.mən/

Omen

presagio de buena o mala suerte futura
Meaning
an event regarded as a sign of future good or bad luck
Example
Many people consider a black cat crossing your path a bad omen.
Muchas personas consideran que un gato negro cruzando tu camino es un mal presagio.
C2 adjective /ˌoʊvərˈwiːnɪŋ/

overweening

excesivamente arrogante
Meaning
excessively arrogant or prideful
Example
His overweening pride cost him many friends.
Su exceso de orgullo le costó muchos amigos.
A1 adverb /aʊt/

out

fuera
Meaning
moving or appearing away from the inside or center; not at home or present
Example
He stepped out of the room quietly.
Él salió de la habitación en silencio.
C1 noun /ˈɔːrθədɑːksi/

orthodoxy

ortodoxia
Meaning
traditional or generally accepted beliefs and practices
Example
The religious leader defended the orthodoxy of the faith.
El líder religioso defendió la ortodoxia de la fe.
C2 noun /oʊliˈændər/

Oleander

oleandro
Meaning
a poisonous evergreen shrub with clusters of white, pink, or red flowers
Example
The beautiful oleander flowers bloomed in the garden despite their toxic nature.
Las hermosas flores de oleandro florecieron en el jardín a pesar de su naturaleza tóxica.
A1 adverb /ɔːf/

off

apagado
Meaning
away from a place, position, or time; not functioning
Example
He turned off the light before leaving the room.
Apagó la luz antes de salir de la habitación.
C1 adjective /ˈɒm.ɪ.nəs/

Ominous

ominoso; amenazante
Meaning
giving the impression that something bad will happen; threatening; foreboding
Example
The dark clouds looked ominous before the storm.
Las nubes oscuras se veían ominosas antes de la tormenta.
C1 noun /əbˈdʒɛktər/

objector

opositor
Meaning
a person who expresses opposition or disapproval to something
Example
The objector raised his concerns during the town meeting.
El opositor expresó sus preocupaciones durante la reunión del consejo.
B2 noun /ˈaʊt.saɪ.dər/

Out-sider

extranjero
Meaning
a person who does not belong to a particular group; someone not accepted by a group
Example
As an outsider, he found it difficult to understand their traditions.
Como extranjero, le resultó difícil entender sus tradiciones.
B2 noun /ˈɑp.tə.mɪst/

Optimist

optimista
Meaning
a person who tends to be hopeful and confident about the future; someone who sees the good side of things
Example
As an optimist, she always believed things would improve.
Como optimista, siempre creyó que las cosas mejorarían.
B2 adjective /əˈfen.sɪv/

Offensive

ofensivo; insultante; agresivo
Meaning
causing displeasure or resentment; insulting; aggressive
Example
His offensive remarks hurt everyone's feelings.
Sus comentarios ofensivos lastimaron los sentimientos de todos.
B2 noun /ˈɒpəreɪtər/

operator

operador
Meaning
a person who operates equipment, a business, or controls something
Example
The machine operator ensured that everything ran smoothly.
El operador de la máquina se aseguró de que todo funcionara sin problemas.
C2 noun /ɒkˈteɪvoʊ/

octavo

octavo (tamaño de libro resultante de doblar una hoja en ocho partes)
Meaning
A size of book page resulting from folding a sheet of paper into eight leaves (sixteen pages).
Example
The old library contained rare octavo editions of Shakespeare.
La antigua biblioteca contenía ediciones raras de octavo de Shakespeare.
C1 verb /ˌoʊvərˈrʌn/

overrun

invadir
Meaning
to spread over or occupy completely; to exceed a limit or time
Example
The garden was overrun with weeds.
El jardín estaba invadido de maleza.
B2 noun oʊˈbiː.sə.t̬i

obesity

obesidad
Meaning
The condition of being grossly fat or overweight.
Example
Obesity increases the risk of diabetes and heart disease.
La obesidad aumenta el riesgo de diabetes y enfermedades cardíacas.
C2 adjective /əˈrækjələr/

oracular

oracular
Meaning
Resembling an oracle; giving wise, mysterious, or prophetic statements
Example
Her oracular words left the audience deep in thought.
Sus palabras oraculares dejaron a la audiencia profundamente pensativa.
A2 adjective /ɒd/

Odd

extraño; inusual; diferente de lo que es normal o esperado
Meaning
strange; unusual; different from what is normal or expected
Example
That's an odd way to solve the problem.
Esa es una forma extraña de resolver el problema.
C1 adjective /ˌaʊtˈspoʊkən/

Outspoken

franco
Meaning
frank; speaking directly
Example
She is known for being outspoken about social issues.
Es conocida por ser franca sobre los problemas sociales.
C2 noun /ˌɑːpərˈtuːnɪzəm/

opportunism

oportunismo
Meaning
The practice of taking advantage of opportunities regardless of principles or ethics.
Example
His decision was driven by opportunism, not values.
Su decisión fue impulsada por el oportunismo, no por los valores.
C1 verb /ˈɒs.ɪ.leɪt/

oscillate

moverse o balancearse de un lado a otro entre dos puntos o estados
Meaning
To swing or move back and forth between two points or states
Example
The stock market tends to oscillate during uncertain times.
El mercado de valores tiende a oscilar durante tiempos inciertos.
C1 noun /ˈoʊvərˌtoʊn/

overtone

implicación sutil
Meaning
A subtle quality, implication, or additional meaning beyond the obvious.
Example
His speech had political overtones that were hard to ignore.
Su discurso tenía connotaciones políticas que eran difíciles de ignorar.
B2 noun ˈoʊzoʊn dɪˈpliʃən

ozone depletion

depleción de ozono
Meaning
The reduction in the amount of ozone in the Earth's stratosphere, leading to increased UV radiation.
Example
Ozone depletion increases UV radiation.
La depleción de ozono aumenta la radiación UV.
C1 adjective /əbˈsɛsɪv/

obsessive

obsesivo
Meaning
Relating to or characterized by an obsession; thinking about something too much.
Example
He has an obsessive interest in cleanliness.
Él tiene un interés obsesivo en la limpieza.
C1 adjective /ˈɑp.ər.ə.tɪv/

Operative

activo; en efecto; funcionando; operativo;
Meaning
Functioning; in effect; working; active;
Example
The new safety protocols became operative immediately after the accident.
Los nuevos protocolos de seguridad se volvieron operativos inmediatamente después del accidente.
C1 noun /ˈaʊtriːtʃ/

outreach

expansión de la asistencia
Meaning
The act of providing services or support to people who might not otherwise have access to them.
Example
The charity launched a new outreach program for the homeless.
La caridad lanzó un nuevo programa de expansión de la asistencia para las personas sin hogar.
A1 conjunction /ɔːr/

or

o
Meaning
used to link alternatives
Example
You can have tea or coffee.
Puedes tomar té o café.
B1 verb /oʊ/

owe

deber
Meaning
to be under obligation to pay or repay; to be indebted
Example
I owe my success to my parents' support.
Le debo mi éxito al apoyo de mis padres.
C1 adjective ˈɒptɪmaɪzd

optimized

optimizados, mejorado, más eficiente
Meaning
Made as fully perfect, functional, or effective as possible; improved to achieve maximum efficiency.
Example
The system has been optimized for faster performance.
El sistema ha sido optimizado para un rendimiento más rápido.
C1 adjective /ˌɔː.riˈen.təl/

Oriental

relativo a los países del Este de Asia; oriental
Meaning
relating to the countries of East Asia; eastern
Example
The museum has a beautiful collection of oriental art.
El museo tiene una hermosa colección de arte oriental.
C1 adjective /ˌaʊt əv ðə ˈweɪ/

out-of-the-way

apartado o remoto
Meaning
remote or unusual; not in a convenient or usual location
Example
They stayed in an out-of-the-way village.
Se quedaron en una aldea apartada.
C2 verb /ˈɑːskjʊleɪt/

osculate

besar
Meaning
To kiss.
Example
They osculated under the mistletoe during the party.
Ellos se besaron debajo del muérdago durante la fiesta.
B2 noun /ˈɒp.tɪ.mɪ.zəm/

optimism

optimismo
Meaning
Hopefulness and confidence about the future or the successful outcome of something.
Example
Her optimism helped her overcome difficult times.
Su optimismo le ayudó a superar tiempos difíciles.
C1 verb /əˈprɛs/

oppress

oprimir
Meaning
to keep someone down by harsh and unfair use of authority; to suppress
Example
The dictator oppressed the people for decades.
El dictador oprimió a la gente durante décadas.
C2 adjective /ˈɒfɪʃ/

offish

distante
Meaning
Unfriendly, distant, or reserved in manner.
Example
He seemed offish at the party and avoided most conversations.
Parecía distante en la fiesta y evitaba la mayoría de las conversaciones.
C1 noun /ɒpˈtɒmɪtrɪst/

optometrist

optometrista
Meaning
A healthcare professional who examines eyes and prescribes corrective lenses.
Example
The optometrist prescribed new glasses for her.
El optometrista le recetó nuevos anteojos.
A2 verb /ˈɔːfər/

offer

ofrecer
Meaning
to present something for acceptance or rejection; to propose
Example
She offered to help with the project.
Ella se ofreció a ayudar con el proyecto.
C2 verb /əbˈtruːd/

obtrude

obstruir
Meaning
to force oneself or one's ideas into a situation uninvited or inappropriately
Example
He didn’t want to obtrude into their private conversation.
Él no quería obstruir su conversación privada.
C2 adjective /ˈoʊdiəs/

odious

odioso
Meaning
extremely unpleasant or repulsive
Example
The dictator was remembered for his odious crimes.
El dictador fue recordado por sus odiosos crímenes.
B1 noun /ˈɑp.ʃən/

Option

opción
Meaning
a thing that is or may be chosen; an alternative course of action
Example
You have the option to work from home or office.
Tienes la opción de trabajar desde casa o desde la oficina.
C2 adjective /əˈfɪʃəs/

officious

entrometido
Meaning
Excessively eager to offer unwanted help or advice; meddlesome.
Example
The officious guard kept interrupting the visitors with unnecessary instructions.
El guardia entrometido interrumpía a los visitantes con instrucciones innecesarias.
C1 verb /aʊst/

oust

destituir
Meaning
To remove someone from a position or place of power or authority.
Example
The rebels ousted the dictator from power.
Los rebeldes destituyeron al dictador del poder.
C1 noun /oʊˈmɪʃ.ən/

Omission

omisión; exclusión
Meaning
the action of excluding or leaving out someone or something; a failure to include
Example
The omission of his name from the list was intentional.
La omisión de su nombre de la lista fue intencional.
C1 adjective ˈɒk.sɪ.də.tɪv

oxidative

Relacionado con la oxidación
Meaning
Related to or caused by oxidation, especially cellular damage from free radicals.
Example
Excess stress can lead to oxidative damage in cells.
El estrés excesivo puede causar daño oxidativo en las células.
B2 noun /ˈɔɪ.stər/

Oyster

ostra
Meaning
a type of shellfish that can be eaten and sometimes contains pearls
Example
She ordered fresh oysters at the seafood restaurant.
Ella ordenó ostras frescas en el restaurante de mariscos.
C1 adjective /ˌəʊ.vərˈɑː.tʃɪŋ/

overarching

global, abarcante, integral
Meaning
Comprehensive or all-embracing; forming an arch over something.
Example
The overarching theme of the book is human resilience.
El tema global del libro es la resistencia humana.
C2 noun (plural) /ˈɔːrdʒiːz/

orgies

orgías
Meaning
Wild gatherings involving excessive indulgence in food, drink, or sexual activity.
Example
The ancient Romans were infamous for their lavish feasts and orgies.
Los antiguos romanos eran infames por sus banquetes lujosos y orgías.
A2 noun /ˈʌv.ən/

Oven

horno
Meaning
an enclosed compartment used for heating, baking, or drying food
Example
She baked cookies in the oven for thirty minutes.
Ella horneó galletas en el horno durante treinta minutos.
B1 noun /aʊl/

Owl

búho
Meaning
a nocturnal bird of prey with large eyes and a hooked beak
Example
The owl hooted softly in the darkness of the forest.
El búho hooteó suavemente en la oscuridad del bosque.
C1 noun /əbˈzɜːvəns/

observance

observancia
Meaning
The practice of following a custom, rule, or religious law.
Example
The festival is held in observance of a centuries-old tradition.
El festival se celebra en observancia de una tradición centenaria.
B2 noun /ˈaʊtɪŋ/

outing

excursión
Meaning
a short trip or excursion, often for leisure or enjoyment
Example
They had a lovely outing at the beach last weekend.
Tuvieron una maravillosa excursión en la playa el fin de semana pasado.
A2 adjective /ˈɑp.ə.zɪt/

Opposite

opuesto; completamente diferente; cara a cara; inverso;
Meaning
Contrary; completely different; facing each other; reverse;
Example
They have opposite views on politics but remain good friends.
Tienen puntos de vista opuestos sobre la política, pero siguen siendo buenos amigos.
B2 noun /ˈaʊt.breɪk/

Out-break

brote
Meaning
a sudden occurrence or eruption of something, especially disease or violence
Example
The outbreak of flu affected many students in the school.
El brote de gripe afectó a muchos estudiantes en la escuela.
B1 noun /ˈɒbstəkəlz/

obstacles

obstáculos
Meaning
Things that block one's way or prevent or hinder progress.
Example
Obstacles in life can often lead to valuable lessons.
Los obstáculos en la vida a menudo conducen a lecciones valiosas.
B2 adjective /ˌɔːɡənaɪˈzeɪʃənəl/

organizational

organizacional
Meaning
relating to the structure or arrangement of a company or group
Example
He works on improving the organizational structure of the company.
Él trabaja en mejorar la estructura organizacional de la empresa.
B2 verb /ˌoʊvərˈloʊd/

overload

sobrecargar
Meaning
to load with too much weight or cargo; to give too much work or information
Example
Don't overload the washing machine or it might break down.
No sobrecargues la lavadora o podría romperse.
C1 noun /ˈaʊtˌkraɪ/

outcry

protesta
Meaning
A strong expression of public anger or disapproval.
Example
The decision sparked an outcry among the citizens.
La decisión provocó una protesta entre los ciudadanos.
C1 verb /əˈfɪʃieɪt/

officiate

oficiar
Meaning
To perform official duties, especially in a ceremony or as a referee.
Example
The priest will officiate the wedding ceremony.
El sacerdote oficiará la ceremonia de la boda.
B1 noun /ˌɑk.jəˈpeɪ.ʃən/

Occupation

ocupación; profesión; toma de control
Meaning
a job or profession; the action of taking control of a place
Example
Teaching is her chosen occupation.
La enseñanza es su ocupación elegida.
A1 pronoun /ˈʌðərz/

others

otros
Meaning
people or things distinct from the ones already mentioned or known
Example
I like to spend time with others.
Me gusta pasar tiempo con otros.
B1 noun ˌɒpəˈtjuːnɪtiz

opportunities

oportunidades
Meaning
A set of circumstances that makes it possible to do something; chances for advancement or success.
Example
Opportunities for jobs decreased.
Las oportunidades para trabajos disminuyeron.
B2 adjective /ˈɒnɡəʊɪŋ/

ongoing

en curso
Meaning
continuing; still in progress
Example
The ongoing project will finish next month.
El proyecto en curso terminará el próximo mes.
C1 adjective /oʊˈbiːs/

obese

obeso
Meaning
Extremely overweight; having an excessive amount of body fat.
Example
The doctor advised the obese patient to adopt a healthier lifestyle.
El doctor le recomendó al paciente obeso adoptar un estilo de vida más saludable.
C2 noun /ɒmˈnɪʃəns/

omniscience

omnisciencia
Meaning
the state of knowing everything
Example
The novel's narrator has an air of omniscience, revealing every character's thoughts.
El narrador de la novela tiene un aire de omnisciencia, revelando los pensamientos de cada personaje.
B2 noun /ˈoʊ.dər/

Odour

olor
Meaning
a distinctive smell, especially an unpleasant one
Example
The odour of fresh bread filled the kitchen.
El olor de pan fresco llenó la cocina.
B2 verb /ˌoʊvərˈpeɪ/

overpay

pagar en exceso
Meaning
To pay more than is necessary or reasonable.
Example
She realized she had overpaid for the concert tickets.
Ella se dio cuenta de que había pagado de más por las entradas del concierto.
C1 noun /ˌɒbstəˈtrɪʃən/

obstetrician

obstetra
Meaning
A doctor specializing in pregnancy, childbirth, and women's reproductive health.
Example
The obstetrician monitored the mother’s health throughout the pregnancy.
El obstetra monitoreó la salud de la madre durante el embarazo.
C1 adjective /əbˈtjuːs/

Obtuse

tonto; obtuso; lento de comprensión
Meaning
annoyingly insensitive or slow to understand; lacking in intelligence or perception
Example
He was being deliberately obtuse about the instructions.
Él estaba siendo deliberadamente obtuso sobre las instrucciones.
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃənz

organizations

organizaciones
Meaning
Organized groups of people with a particular purpose
Example
Organizations play a key role in policymaking.
Las organizaciones desempeñan un papel clave en la toma de decisiones políticas.
C1 verb /ˈɒfsɛt/

offset

compensar
Meaning
To counterbalance or compensate for something.
Example
The company's losses were offset by gains in other departments.
Las pérdidas de la compañía fueron compensadas por las ganancias en otros departamentos.
B2 verb /əˈfend/

offend

ofender
Meaning
to cause displeasure or resentment; to hurt someone's feelings
Example
His rude comments offended many people at the meeting.
Sus comentarios groseros ofendieron a muchas personas en la reunión.
B2 noun /ˈaʊtlet/

outlet

salida
Meaning
a means by which something is released, expressed, or distributed
Example
Art is a great outlet for emotions.
El arte es una gran salida para las emociones.
A1 adjective /oʊld/

old

viejo
Meaning
having lived for a long time; not new or young
Example
He still drives his old car.
Él todavía conduce su coche viejo.
C2 adjective /ˈoʊ.kən/

oaken

hecho de roble
Meaning
made of or resembling oak wood
Example
The villagers gathered around the oaken table in the hall.
Los aldeanos se reunieron alrededor de la mesa de roble en el salón.
C2 adjective /ɑːlˈfæktəri/

olfactory

olfatorio
Meaning
Relating to the sense of smell.
Example
The perfume activated her olfactory nerves immediately.
The perfume activated her olfactory nerves immediately.
B2 noun, verb /ˈaʊtlɔː/

outlaw

forajido, ilegalizar
Meaning
as a noun: a person who breaks the law and lives outside its protection; as a verb: to make something illegal
Example
The government decided to outlaw the harmful practice.
El gobierno decidió ilegalizar la práctica perjudicial.
C2 verb /aʊtˈraɪd/

outride

adelantar
Meaning
to ride faster, farther, or better than someone else
Example
The young rider managed to outride his competitors in the race.
El joven jinete logró adelantar a sus competidores en la carrera.
B2 noun /ˈɔr.fən/

Orphan

huérfano
Meaning
a child whose parents are dead; someone without protective support
Example
The orphan was adopted by a loving family.
El huérfano fue adoptado por una familia amorosa.
A2 noun /ˈʌn.jən/

Onion

cebolla
Meaning
a round vegetable with a strong taste and smell, made up of many layers
Example
I need to chop some onions for the curry recipe.
Necesito cortar algunas cebollas para la receta de curry.
C1 verb /ˈɒp.tɪ.maɪz/

optimize

optimizar
Meaning
To make the best or most effective use of a situation, opportunity, or resource.
Example
The company is working to optimize its supply chain.
La empresa está trabajando para optimizar su cadena de suministro.
A1 adjective /ˈɔːr.ɪndʒ/

Orange

naranja
Meaning
having a color between red and yellow like that of a ripe orange fruit
Example
The orange sunset painted the sky magnificently.
El atardecer naranja pintó el cielo magníficamente.
C1 noun /ˌəʊvərɪksˌplɔɪˈteɪʃən/

overexploitation

sobreexplotación
Meaning
The unsustainable use of natural resources at a rate that exceeds their ability to regenerate, leading to depletion and environmental degradation.
Example
Overexploitation of natural resources leads to environmental degradation.
La sobreexplotación de los recursos naturales conduce a la degradación ambiental.
B2 noun /ˈoʊtˌmiːl/

oatmeal

avena cocida
Meaning
A type of porridge made from ground oats, often eaten for breakfast.
Example
She eats a bowl of oatmeal every morning for breakfast.
Ella come un tazón de avena cocida todas las mañanas para el desayuno.
C1 verb /ˌoʊvərˈʃædoʊ/

overshadow

opacar
Meaning
to appear more important or significant than something else, reducing its impact
Example
The scandal overshadowed his achievements.
El escándalo opacó sus logros.
B1 verb /ˈɒpəreɪtɪŋ/

operating

operando
Meaning
to control or manage the functioning of something
Example
The company has been operating in this market for five years.
La compañía ha estado operando en este mercado durante cinco años.
C1 noun /ˈɔːrdɪnəns/

ordinance

ordenanza
Meaning
An authoritative rule, law, or decree issued by a city, town, or authority.
Example
The city council passed an ordinance banning smoking in public parks.
El consejo municipal aprobó una ordenanza que prohíbe fumar en los parques públicos.
C2 adjective /ˈɑːbdjʊrət/

obdurate

obstinado
Meaning
Stubbornly refusing to change one's opinion or course of action.
Example
He remained obdurate despite everyone's pleas.
Él permaneció obstinado a pesar de las súplicas de todos.
C1 verb /ˌaʊtˈduː/

outdo

superar
Meaning
To do better than someone else; to surpass.
Example
She always tries to outdo her classmates in exams.
Ella siempre trata de superar a sus compañeros de clase en los exámenes.
B2 noun/verb /ˈaʊtreɪdʒ/

outrage

indignación
Meaning
A strong feeling of anger and shock; to arouse anger or shock.
Example
The unfair decision caused public outrage.
La decisión injusta causó una indignación pública.
B2 adjective ɔːrˈɡæn.ɪk

organic

orgánico
Meaning
Produced or involving production without the use of chemical fertilizers, pesticides, or other artificial agents.
Example
Organic farming improves soil health and reduces pollution.
La agricultura orgánica mejora la salud del suelo y reduce la contaminación.
A2 adjective /ˈɔː.dɪ.nər.i/

Ordinary

ordinario; común; no especial
Meaning
normal; usual; not special
Example
It was just an ordinary day at the office.
Era solo un día ordinario en la oficina.
A1 interjection /oʊ/

oh

¡Oh!
Meaning
used to express surprise, realization, or understanding
Example
Oh, I didn't know you were here!
¡Oh, no sabía que estabas aquí!
B2 noun /ˌɑb.zɚˈveɪ.ʃən/

Observation

observación
Meaning
the action of watching something carefully; a comment or remark
Example
The scientist made careful observations of the experiment.
El científico hizo observaciones cuidadosas del experimento.
B2 noun /ˈɒs.trɪtʃ/

Ostrich

avestruz
Meaning
a large flightless bird native to Africa with long legs and neck
Example
The ostrich is the world's largest bird.
El avestruz es el pájaro más grande del mundo.
C2 noun /əbˈsɪdiən/

obsidian

obsidiana (roca volcánica oscura y vidriosa)
Meaning
A hard, dark, glasslike volcanic rock formed by rapid solidification of lava.
Example
The knife was made from sharp obsidian.
El cuchillo estaba hecho de obsidiana afilada.
B1 verb /ˈɒpəreɪt/

operate

operar
Meaning
to function; to control or manage; to perform surgery
Example
The surgeon will operate on the patient tomorrow.
El cirujano operará al paciente mañana.
C1 verb /aʊtˈlæst/

outlast

perdurar más tiempo que
Meaning
to continue longer than; to endure beyond someone or something else
Example
The old castle has outlasted many generations.
El viejo castillo ha perdurado más que muchas generaciones.
C1 verb /ˌoʊvərˈpaʊər/

overpower

dominar
Meaning
To defeat or gain control over someone or something by using greater strength or force.
Example
The soldiers managed to overpower the enemy forces.
Los soldados lograron dominar las fuerzas enemigas.
B1 noun /əˈpɪn.jən/

Opinion

opinión
Meaning
a view or judgment formed about something; a belief or assessment based on grounds short of proof
Example
In my opinion, this is the best solution.
En mi opinión, esta es la mejor solución.
C1 adjective /əˈkʌlt/

occult

oculto
Meaning
Relating to mysterious, supernatural, or magical powers and practices.
Example
She had always been fascinated by the occult and its hidden knowledge.
Ella siempre estuvo fascinada por lo oculto y su conocimiento oculto.
C2 verb ˈɑːb.fə.skeɪt

obfuscate

ofuscar, oscurecer, confundir
Meaning
Render obscure, unclear, or unintelligible.
Example
Politicians often obfuscate facts to mislead people.
Los políticos a menudo ofuscan los hechos para engañar a la gente.
C1 adjective əʊˈpeɪk

opaque

opaco, impenetrable, difícil de entender
Meaning
Not able to be seen through; not transparent; difficult to understand.
Example
The glass was too opaque to see through.
El vidrio era tan opaco que no se podía ver a través de él.
C1 verb /ˌaʊtˈweɪ/

outweigh

ser más importante
Meaning
To be more important, valuable, or significant than something else.
Example
The benefits of the new policy outweigh the risks.
Los beneficios de la nueva política superan los riesgos.
C1 adjective /əbˈnɒkʃəs/

Obnoxious

odioso
Meaning
extremely unpleasant; offensive; annoying
Example
His obnoxious behavior at the party annoyed everyone.
Su comportamiento odioso en la fiesta molestó a todos.
C1 adjective /ˈaʊt.kɑːst/

Outcast

rechazado
Meaning
rejected by society; excluded person
Example
He felt like an outcast in his new school.
Él se sintió como un rechazado en su nueva escuela.
B2 noun /ɔːrˈɡæn.ɪk ˈfɑːr.mɪŋ/

organic farming

agricultura orgánica
Meaning
Farming method that avoids synthetic chemicals and fertilizers, using natural methods instead.
Example
Organic farming improves soil health and reduces pollution.
La agricultura orgánica mejora la salud del suelo y reduce la contaminación.
C2 noun /ˈɒkjʊlɪst/

oculist

optometrista
Meaning
An old-fashioned term for an eye doctor or ophthalmologist.
Example
The village oculist was known for treating various eye diseases.
El oculista del pueblo era conocido por tratar diversas enfermedades oculares.
C2 noun /ˌɔːrnɪˈθɒlədʒɪst/

ornithologist

ornitólogo
Meaning
a scientist who studies birds
Example
The ornithologist spent years studying migratory birds.
El ornitólogo pasó años estudiando aves migratorias.
C1 verb /uːz/

ooze

filtrarse
Meaning
to slowly flow or leak out through small openings or pores
Example
Blood began to ooze from the small cut.
La sangre comenzó a filtrarse de la pequeña herida.
A1 noun/adjective/adverb /ˌaʊtˈsaɪd/

outside

afuera
Meaning
the external part or surface of something; beyond the boundary
Example
Children were playing outside in the yard.
Los niños estaban jugando afuera en el jardín.
A2 noun /əˈlɪmpɪks/

olympics

Juegos Olímpicos
Meaning
an international sports competition held every four years with athletes from many countries
Example
The Olympics bring athletes from all over the world together.
Los Juegos Olímpicos reúnen a atletas de todo el mundo.