irrepressible
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C1 adjective /ˌɪrɪˈprɛsəbl̩/

irrepressible

抑制できない
Meaning
Impossible to control or restrain.
Example
She had an irrepressible urge to laugh during the speech.
彼女はスピーチ中に抑制できない笑いの衝動を隠すことができませんでした。
C1 adjective ɪmˈpɛkəbl

impeccable

完璧な
Meaning
In accordance with the highest standards; faultless.
Example
His impeccable taste in fashion was admired by all his peers.
彼の完璧なファッションセンスは、すべての同僚に賞賛されました。
C1 adjective /ɪmˈpɛn.ɪ.trə.bəl/

impenetrable

Meaning
Impossible to pass through or enter; impossible to understand.
Example
The dense forest was nearly impenetrable.
C1 adjective /ɪmˈprɒbəbl/

improbable

あり得ない
Meaning
Not likely to be true or to happen.
Example
It seems improbable that he will arrive on time.
彼が時間通りに到着するのはあり得ないようだ。
C1 noun /ɪnˈɛk.wɪ.ti/

inequity

不平等
Meaning
Lack of fairness or justice; unequal distribution or treatment.
Example
Social inequity continues to be a global issue.
社会的不平等は依然としてグローバルな問題です。
C1 noun ˌɪnsjʊˈleɪʃən

insulation

絶縁
Meaning
Material used to prevent heat, sound, or electricity from being transmitted from one area to another.
Example
Insulation of food storage areas can prevent pests from entering.
食品保管エリアの絶縁は、害虫が侵入するのを防ぐことができます。
C1 noun /ˌɪnɪkˈspɪəriəns/

inexperience

未経験
Meaning
Lack of knowledge or skill in a particular activity or field.
Example
His inexperience in handling negotiations was evident.
交渉における彼の未経験は明らかでした。
C1 noun /ɪmˈbæl.əns/

Imbalance

不均衡
Meaning
lack of proportion or relation between corresponding things; unequal distribution
Example
The doctor said the patient's dizziness was caused by an inner ear imbalance.
医者は患者のめまいが内耳の不均衡によって引き起こされたと言いました。
C1 noun /ɪnˌtɪmɪˈdeɪʃən/

intimidation

威圧
Meaning
The action of frightening or threatening someone to make them do something.
Example
The workers reported cases of intimidation by the management.
労働者たちは経営陣による威圧の事例を報告しました。
C1 noun /ˈɪntərˌpleɪ/

interplay

相互作用
Meaning
The way in which two or more things have an effect on each other.
Example
The interplay between culture and technology shapes modern life.
文化と技術の相互作用が現代生活を形作っています。
C1 noun /ˈɪn.floʊ/

inflow

流入
Meaning
The movement of things such as money, people, or water into a place.
Example
The inflow of tourists boosted the local economy.
観光客の流入が地域経済を活性化させた。
C1 noun /ɪmˈpɛd.ɪ.mənt/

impediment

障害
Meaning
A hindrance or obstruction in doing something; something that prevents progress.
Example
Lack of funds is a major impediment to the project.
資金不足はプロジェクトの大きな障害です。
C1 adjective /ɪnˈtɜːrmənəbl/

interminable

終わりのない
Meaning
Seemingly endless; having no apparent end.
Example
The meeting felt interminable and exhausting.
会議は終わりのない疲れるもののように感じた。
C1 noun /ˈɪnsɪdəns/

incidence

発生率
Meaning
the occurrence, rate, or frequency of something
Example
The incidence of road accidents has decreased this year.
今年の道路事故の発生率は減少しました。
C1 verb /ɪnˈstɪl/

instill

植え付ける
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.
親は子供に良い価値観を植え付けようとしています。
C1 adjective /ɪnˈvæljʊəbl/

invaluable

計り知れない価値がある
Meaning
Extremely useful or indispensable.
Example
Her advice proved invaluable to my success.
彼女の助言は私の成功にとって非常に貴重でした。
C1 noun ˌɪn.ɪˈfɪʃ.ən.si

inefficiency

非効率
Meaning
The state or quality of not achieving maximum productivity; failure to make the best use of time or resources.
Example
Government inefficiency leads to slow project completion.
政府の非効率性がプロジェクトの完了を遅らせる。
C1 adjective /ˌɪməˈtɪəriəl/

immaterial

無関係
Meaning
Not important or relevant; lacking physical substance.
Example
The judge ruled that the argument was immaterial to the case.
裁判官はその議論が事件に関係ないと判断しました。
C1 adjective /ˌɪrɪˈvɜːrsəbl/

irreversible

不可逆な
Meaning
Not able to be undone, changed, or reversed.
Example
The damage caused by the fire was irreversible.
火事によって生じた損害は不可逆でした。
C1 adjective /ɪnˈsteɪbəl/

instable

不安定な
Meaning
not stable; liable to change, collapse, or fail; lacking firmness or reliability
Example
The instable political situation worried foreign investors.
不安定な政治状況が外国の投資家を心配させた。
C1 noun /ˌɪnfɪˈdɛləti/

infidelity

不倫
Meaning
the act of being unfaithful to a spouse or partner
Example
Their marriage ended due to his infidelity.
彼らの結婚は彼の不倫が原因で終わった。
C1 adverb /ˌɪn.dɪˈskrɪm.ɪ.nət.li/

Indiscriminately

無差別に
Meaning
without making careful distinctions; randomly; without discrimination
Example
The company fired employees indiscriminately without considering their performance.
会社は従業員を彼らのパフォーマンスを考慮せずに無差別に解雇しました。
C1 noun /ɪnˈsɒm.ni.ə/

Insomnia

不眠症
Meaning
habitual sleeplessness; inability to sleep; the condition of being unable to sleep
Example
Her chronic insomnia made it difficult for her to concentrate during work hours.
彼女の慢性的な不眠症は、仕事中に集中するのを難しくさせた。
C1 noun /ɪˈmiːdiəsi/

immediacy

即時性, 緊迫感
Meaning
The quality of bringing one into direct and instant involvement with something, giving rise to a sense of urgency or excitement.
Example
The immediacy of digital communication has reshaped business operations.
デジタルコミュニケーションの即時性は、ビジネスの運営方法を変えました。
C1 noun /ˈɪntərˌluːd/

interlude

間奏
Meaning
A short period of time that comes between two events; an interval.
Example
There was a brief musical interlude between the two acts of the play.
演劇の二つの幕の間に短い音楽の間奏がありました。
C1 noun ˌɪndɪˈspensəbl səˈpɔːrt

indispensable support

欠かせないサポート
Meaning
Essential assistance that cannot be done without; absolutely necessary help.
Example
Volunteers provide indispensable support to communities.
ボランティアはコミュニティに欠かせないサポートを提供しています。
C1 adjective /ɪˈniː.bri.eɪ.tɪd/

inebriated

酔っ払った
Meaning
under the influence of alcohol; drunk
Example
He stumbled into the room completely inebriated.
彼は完全に酔っ払って部屋に入ってきた。
C1 noun /ɪnˈvɜːrʒən/

inversion

逆転
Meaning
A reversal of the normal order, position, or relationship.
Example
In poetry, inversion is often used to create emphasis.
詩では、逆転は強調を作るためによく使われます。
C1 adjective /ˌaɪ.di.əˈlɒdʒ.ɪ.kəl/

ideological

イデオロギー的
Meaning
Relating to or based on a system of ideas or beliefs.
Example
The two parties are divided by deep ideological differences.
二つの党は深いイデオロギー的な違いによって分裂している。
C1 adjective /ˌɪnstənˈteɪniəs/

instantaneous

即時
Meaning
Happening immediately, without any delay.
Example
The change in temperature was almost instantaneous.
温度の変化はほぼ即時でした。
C1 adjective ˌɪn.trəˈspek.tɪv

introspective

内省的
Meaning
Characterized by or given to introspection; examining one's own thoughts and feelings.
Example
Writers tend to be highly introspective individuals.
作家はしばしば非常に内省的な人々である。
C1 adverb /ɪnˈvɜːrs.li/

Inversely

逆に; 反対に
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.
商品の価格は市場での入手可能性に逆に関連しています。
C1 adjective /ˌɪnədˈmɪsəbl̩/

inadmissible

受け入れられない
Meaning
Not allowed, especially as evidence in a court of law.
Example
The judge ruled the evidence inadmissible.
裁判官は証拠を受け入れられないと判断しました。
C1 noun /ˌɪmpɔːrˈteɪʃən/

importation

輸入
Meaning
The act of bringing goods or services into a country from abroad
Example
The importation of luxury goods is strictly regulated.
高級品の輸入は厳しく規制されています。
C1 adjective /ˌɪndɪˈskrɪmɪnət/

indiscriminate

無差別
Meaning
Done without careful judgment; random or haphazard.
Example
The indiscriminate use of pesticides harms the environment.
農薬の無差別な使用は環境に害を与えます。
C1 adjective /ˌɪnkənˈsɪdərət/

inconsiderate

思いやりがない
Meaning
Thoughtless; showing a lack of concern for others.
Example
It was inconsiderate of him to play loud music late at night.
夜遅くに大きな音で音楽を流すことは、思いやりがない行動でした。
C1 noun /ɪnˈtɛstɪn/

intestine

腸
Meaning
The part of the digestive system where food is digested and absorbed, extending from the stomach to the anus.
Example
The doctor explained how nutrients are absorbed in the small intestine.
医者は、小腸で栄養素がどのように吸収されるかを説明しました。
C1 adjective /ɪmˈpæʃənd/

impassioned

情熱的な
Meaning
Filled with or showing great emotion.
Example
She gave an impassioned speech about human rights.
彼女は人権について情熱的なスピーチを行いました。
C1 verb /ɪnˈvɜːrt/

invert

逆さにする
Meaning
To turn something upside down or in the opposite position, order, or direction.
Example
He inverted the glass to let the water drain out.
彼は水が流れ出るようにグラスを逆さまにしました。
C1 adjective /ɪˈnɜːrt/

inert

不活性
Meaning
lacking the ability or strength to move or act; chemically inactive
Example
The patient remained inert on the bed.
患者はベッドで動かずにじっとしていました。
C1 adjective /ɪmˈpæsɪv/

impassive

無表情
Meaning
Not showing or feeling emotion; expressionless.
Example
Despite the shocking news, she remained impassive.
衝撃的なニュースにもかかわらず、彼女は無表情のままでした。
C1 adjective /ɪˈmækjələt/

immaculate

完璧
Meaning
perfectly clean, neat, or free from flaws
Example
Her room was immaculate, with everything in its place.
彼女の部屋は完璧で、すべてが所定の位置にありました。
C1 adjective /ɪˈmeʒərəbəl/

Immeasurable

計り知れない
Meaning
too large or extensive to measure; boundless
Example
The immeasurable love of a mother knows no bounds.
母の計り知れない愛には限界がない。
C1 adjective /ɪnˈkwɪzɪtɪv/

inquisitive

好奇心旺盛な
Meaning
Curious or eager to learn and ask questions.
Example
The inquisitive child asked endless questions about the stars.
好奇心旺盛な子供は星について無限に質問をしました。
C1 adjective /ɪmˈprɒmp.tjuː/

impromptu

即興
Meaning
Done without being planned, organized, or rehearsed; spontaneous.
Example
He gave an impromptu speech at the event.
彼はイベントで即興のスピーチを行いました。
C1 noun /ˌɪnækˈtɪvɪti/

inactivity

不活動
Meaning
the state of not being active physically or mentally; lack of action
Example
Prolonged inactivity can negatively affect both physical and mental health.
長期間の不活動は身体的および精神的健康に悪影響を与えます。
C1 adjective /ɪnˈtændʒəbl/

intangible

無形の
Meaning
Unable to be touched or grasped; not having a physical presence.
Example
Trust is an intangible quality in relationships.
信頼は関係において無形の特質です。
C1 adjective /ˌɪnəˈtɛntɪv/

inattentive

不注意な
Meaning
not paying attention; lacking focus or concentration
Example
The inattentive student missed several important instructions.
不注意な学生は重要な指示をいくつも逃した。
C1 adjective /ɪnˈtjuː.ɪ.tɪv/

intuitive

直感的
Meaning
Based on instinctive understanding rather than reasoning.
Example
The software has an intuitive design that makes it easy to use.
そのソフトウェアは直感的なデザインを持っており、使いやすいです。
C1 verb /ɪmˈpɒvərɪʃ/

impoverish

貧困にする
Meaning
To make someone poor or reduce the quality or richness of something.
Example
The long war impoverished the entire nation.
長い戦争が国全体を貧困にした。
C1 adjective /ˌɪmprɪˈsaɪs/

imprecise

不正確
Meaning
Not exact or accurate; vague.
Example
His explanation was too imprecise to be helpful.
彼の説明はあまりにも不正確で役に立たなかった。
C1 noun ɪnˈsɛpʃən

inception

始まり
Meaning
The establishment or starting point of an institution or activity.
Example
The inception of the company marked a new era in the industry.
その企業のインセプションは業界に新しい時代を築きました。
C1 verb /ɪˈmɔːrtəlaɪz/

immortalize

不朽の
Meaning
to preserve the memory of someone or something forever
Example
The statue was built to immortalize the hero’s sacrifice.
その像は、英雄の犠牲を永遠にするために建てられました。
C1 adjective /ɪnˈhɛrənt/

inherent

固有の
Meaning
Existing in something as a natural, permanent, or essential quality.
Example
There are inherent risks in extreme sports.
エクストリームスポーツには固有のリスクが存在する。
C1 verb /ɪnˈkɜːr/

incur

負う
Meaning
To bring upon oneself something undesirable, usually as a result of actions.
Example
He incurred a fine for parking in the wrong place.
彼は間違った場所に駐車して罰金を科せられた。
C1 adjective /ˌɪnɔːrˈɡænɪk/

inorganic

無機の
Meaning
relating to substances that are not derived from living organisms; lacking organic structure or growth
Example
Inorganic compounds are commonly studied in chemistry labs.
無機化合物は化学の基本です。
C1 noun /ɪnˈsek.tɪ.saɪd/

Insecticide

殺虫剤
Meaning
a substance used for killing insects; a chemical pesticide that targets insects
Example
The farmer sprayed insecticide on his crops to protect them from harmful bugs.
農夫は作物を有害な虫から守るために殺虫剤を噴霧しました。
C1 noun /ɪmˈpɒs.tər/

Impostor

詐欺師; 偽者
Meaning
a person who pretends to be someone else in order to deceive others; a fraud
Example
The impostor convinced everyone he was a doctor until his fake credentials were discovered.
詐欺師は医者だとみんなを納得させましたが、彼の偽の資格が発覚するまでそれが続きました。
C1 adjective /ɪnˈflɛksəbl/

inflexible

柔軟性がない
Meaning
Not able to bend or change; unwilling to change ideas or behavior.
Example
His inflexible attitude made negotiations difficult.
彼の柔軟性がない態度は交渉を難しくしました。
C1 noun /ˌɪn.trəˈspek.ʃən/

introspection

内省
Meaning
The examination or observation of one's own mental and emotional processes; self-reflection.
Example
Through introspection, she gained insight into her emotions.
内省を通じて、彼女は自分の感情に対する深い洞察を得ました。
C1 verb /ˌɪntəˈsɛkt/

intersect

交差する
Meaning
to cross or pass through each other
Example
The two roads intersect at the city center.
二つの道路は市内中心で交差する。
C1 adjective /ɪnˈdetɪd/

Indebted

借金がある; 感謝している
Meaning
owing money or gratitude to someone; obligated; grateful
Example
I am deeply indebted to my teacher for all her guidance.
私は先生のすべての指導に深く感謝しています。
C1 verb /ˈɪtəreɪt/

iterate

反復する
Meaning
To repeat a process or statement, often to improve or refine.
Example
The software team will iterate the design until it meets user needs.
ソフトウェアチームは、ユーザーのニーズを満たすまでデザインを繰り返します。
C1 adjective ˌɪn.krəˈmen.təl

incremental

増分的
Meaning
Relating to or denoting an increase or addition, especially one of a series on a fixed scale; proceeding in small stages.
Example
Incremental changes ensure sustainability.
増分的な変化は持続可能性を確保します。
C1 adjective ɪnˈdʒiː.ni.əs

ingenious

独創的
Meaning
Showing inventiveness and skill; clever, original, and inventive.
Example
His ingenious ideas transformed modern physics.
彼の独創的なアイデアは現代物理学を変えました。
C1 noun /ˈɪŋklɪŋ/

inkling

予感
Meaning
A slight idea, hint, or suspicion about something.
Example
She had an inkling that he was planning a surprise.
彼女は彼がサプライズを計画しているという予感を持っていた。
C1 noun /ɪmˈpɜː.mə.nəns/

impermanence

無常
Meaning
The state or fact of lasting for only a limited period of time.
Example
The philosophy of Buddhism emphasizes the impermanence of life.
仏教の哲学は、人生の無常性を強調します。
C1 noun /ˌɪntərˈdʒɛkʃən/

interjection

感嘆詞
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.
'わお'や'痛っ'は英語でよく使われる感嘆詞です。
C1 adjective /ɪnˈfleɪtɪd/

inflated

膨らんだ
Meaning
excessively increased in size, value, or importance; filled with air or gas
Example
The company faced criticism for its inflated prices.
その会社は膨らんだ価格で批判を受けました。
C1 adjective ɪn ˈfleɪ.ʃə.ner.i

inflationary

インフレ的
Meaning
Characterized by or tending to cause monetary inflation; relating to rising prices.
Example
The government took measures to control inflationary pressures.
政府はインフレ圧力を制御するために措置を講じた。
C1 adjective /ɪmˈpɛtʃ.u.əs/

impetuous

衝動的な
Meaning
Acting or done quickly and without thought or care; impulsive.
Example
His impetuous decision led to unexpected consequences.
彼の衝動的な決断は予想外の結果を招いた。
C1 adjective /ɪnˈsʌf.ər.ə.bəl/

insufferable

耐え難い
Meaning
Too extreme to bear; intolerable.
Example
The heat during the summer was insufferable.
夏の暑さは耐え難かった。
C1 adjective /ˌɪrɪˈspɛktɪv/

Irrespective

無視して; 問わず
Meaning
without taking something into account; regardless of
Example
All students will be treated equally, irrespective of their background.
すべての学生は、背景に関係なく平等に扱われます。
C1 adjective /ˌɪntəˈrɑːɡətɪv/

interrogative

疑問の
Meaning
Relating to or conveying a question; in grammar, used to form questions.
Example
She raised an interrogative eyebrow when she heard the news.
彼女はそのニュースを聞いて疑問のまなざしを向けました。
C1 noun ˌɪn.toʊˈneɪ.ʃən

intonation

イントネーション
Meaning
The rise and fall of tone in speech and pronunciation.
Example
Proper intonation enhances the clarity of a speech.
適切なイントネーションはスピーチの明確さを高めます。
C1 noun /ˈɪnkwest/

inquest

調査
Meaning
A legal or official inquiry, especially into the cause of a death.
Example
The inquest revealed the cause of the accident.
調査は事故の原因を明らかにしました。
C1 verb /ɪnˈvælɪdeɪt/

invalidate

無効にする
Meaning
To make something not valid or legally acceptable.
Example
The new evidence may invalidate the previous ruling.
新しい証拠が前の判決を無効にするかもしれません。
C1 verb /ɪnˈtɒksɪkeɪt/

intoxicate

幸せ
Meaning
to make someone lose control of their faculties or behavior due to alcohol or drugs
Example
The strong drink quickly intoxicated him.
彼女は賞を受け取ったとき、自分の幸せを隠すことができなかった。
C1 verb /ɪmˈpiːd/

impede

妨げる
Meaning
To obstruct or hinder the progress or development of something.
Example
Lack of funds can impede business growth.
資金不足はビジネスの成長を妨げる可能性があります。
C1 adverb /ˌɪnsɪˈdɛntəli/

incidentally

ちなみに
Meaning
by the way; used to introduce a remark not directly related to the main subject
Example
Incidentally, did you know that she studied in Paris?
ちなみに、彼女がパリで勉強していたことを知っていましたか？
C1 noun ɪnˌten.sɪ.fɪˈkeɪ.ʃən

intensification

強化
Meaning
The process of becoming or making something more intense or extreme.
Example
The intensification of climate change requires urgent action.
気候変動の強化は緊急の行動を必要とします。
C1 verb /aɪˈdiː.ə.laɪz/

idealize

理想化する
Meaning
To regard or represent something as perfect or better than it really is.
Example
Children often idealize their parents.
子供たちはしばしば親を理想化します。
C1 verb /ˌɪn.trəˈspekt/

introspect

内省する
Meaning
To examine one's own thoughts, feelings, or mental state.
Example
He often introspects before making important decisions.
彼は重要な決定を下す前にしばしば自己分析をします。
C1 adjective /ˈɪɡ.ni.əs/

igneous

火成
Meaning
Formed through the cooling and solidification of magma or lava.
Example
Granite is an igneous rock commonly used in construction.
花崗岩は建設に一般的に使用される火成岩です。
C1 verb /ˈɪnstɪˌɡeɪt/

instigate

扇動する
Meaning
To bring about or initiate an action, often something negative.
Example
He was accused of instigating the riot.
彼は暴動を扇動したとして告発された。
C1 adjective ˌɪn.təˈstel.ər

interstellar

星間の、インターステラ、宇宙の
Meaning
Occurring or situated between stars.
Example
Scientists study interstellar travel possibilities.
科学者たちはインターステラ旅行の可能性を研究しています。
C1 adjective /ˈɪrɪtəbl/

irritable

Meaning
easily annoyed or made angry
Example
She became irritable after working long hours without rest.
C1 noun /ˌɪnflɛksɪˈbɪlɪti/

inflexibility

柔軟性の欠如
Meaning
the quality of being rigid or unwilling to change; lack of adaptability
Example
The inflexibility of the rules caused unnecessary delays.
規則の柔軟性の欠如が不要な遅れを引き起こした。
C1 noun /ˈɪnˌmeɪt/

inmate

囚人
Meaning
a person confined to an institution such as a prison or hospital
Example
The prison has over a thousand inmates.
刑務所には千人以上の囚人がいます。
C1 verb /ɪnˈterəˌɡeɪt/

interrogate

尋問する
Meaning
to ask someone questions in a thorough and formal way; to question intensively
Example
The police interrogated the suspect for hours.
警察は容疑者を何時間も尋問した。
C1 adjective /ɪnˈtɒl.ər.ə.bəl/

Intolerable

耐えられない
Meaning
unable to be endured; extremely unpleasant or painful
Example
The noise from the construction site was intolerable.
工事現場の騒音は耐えられないほどひどかった。
C1 noun ˌɪnfrəˈstrʌktʃərəl dɪˈveləpmənt

infrastructural development

インフラ整備
Meaning
The process of building and improving the basic physical and organizational structures and facilities needed for the operation of a society or enterprise.
Example
Infrastructural development is necessary for efficient recycling.
インフラストラクチャー開発は効率的なリサイクルに必要です。
C1 noun /aɪˈdiː.ə.lɪ.zəm/

Idealism

理想主義
Meaning
the pursuit of high principles and noble goals; unrealistic pursuit of perfection
Example
His youthful idealism motivated him to join various social justice movements.
彼の若い理想主義は、彼を様々な社会正義運動に参加させる原動力となった。
C1 adjective ˈɪn.lənd

Inland

内陸
Meaning
Situated in the interior of a country; away from the coast.
Example
Inland transport boosts local trade.
内陸輸送は地元の貿易を促進します。
C1 adjective ˌɪn.tə.dʒen.əˈreɪ.ʃən.əl

intergenerational

世代間、異なる世代間で発生する
Meaning
Existing or occurring between different generations of a family.
Example
Intergenerational wisdom ensures cultural continuity.
インタージェネレーショナルな知恵は文化的継続性を確保する。
C1 adjective /ɪnˈdefɪnət/

Indefinite

不確定な
Meaning
not clearly defined; uncertain; vague; unlimited in time
Example
The meeting has been postponed for an indefinite period.
会議は不確定な期間に延期されました。
C1 adjective /ɪˈrɛvərənt/

irreverent

不敬な
Meaning
showing a lack of respect for people or things that are usually respected
Example
The comedian’s irreverent jokes offended some of the audience.
コメディアンの不敬なジョークは、観客の一部を不快にさせた。
C1 verb /ɪmˈpɜːrsəneɪt/

impersonate

偽る
Meaning
to pretend to be another person in order to entertain or deceive
Example
He was arrested for trying to impersonate a police officer.
彼は警察官を装おうとしたため逮捕されました。
C1 adjective ɪˈluː.sər.i

illusory

幻の
Meaning
Based on illusion; not real although seeming to be.
Example
His sense of security was entirely illusory.
彼の安全感は完全に幻のものだった。
C1 adjective /ɪmˈpjʊər/

Impure

不純
Meaning
contaminated; not clean; mixed with foreign substances
Example
The impure water caused health problems in the village.
不純な水は村で健康問題を引き起こしました。
C1 verb /ɪmˈpiːtʃ/

impeach

Meaning
To charge a public official with misconduct while in office.
Example
The parliament voted to impeach the president.
C1 adjective ɪnˈdel.ə.bəl

indelible

消えない
Meaning
Making marks that cannot be removed; impossible to forget or remove.
Example
Her speech left an indelible mark on the audience.
彼女のスピーチは聴衆に消えない印象を残しました。
C1 noun /ˈɪrɪtənt/

irritant

刺激物
Meaning
something that causes irritation or discomfort
Example
Dust is a common irritant for people with allergies.
ほこりはアレルギーを持つ人々にとって一般的な刺激物です。
C1 adjective /ɪˈlʌstriəs/

illustrious

著名
Meaning
Well known, respected, and admired for past achievements.
Example
She had an illustrious career in medicine.
彼女は医学の分野で著名なキャリアを持っていた。
C1 noun /ɪnˈsɜːrdʒənt/

insurgent

反乱者
Meaning
A person who rises in revolt against authority or government.
Example
The army arrested several insurgents after the attack.
軍隊は攻撃後、数人の反乱者を逮捕した。
C1 noun/verb /ˈɪmprɪnt/

imprint

刻印
Meaning
A mark or impression made by pressure; to establish or fix firmly in someone's mind.
Example
The event left an indelible imprint on the city's history.
その出来事は都市の歴史に消えない刻印を残した。
C1 adjective /ɪnˈfriːkwənt/

infrequent

稀な
Meaning
Happening rarely or not often.
Example
He made infrequent visits to his hometown after moving abroad.
彼は海外に移住した後、故郷にあまり頻繁に訪れることはありませんでした。
C1 adjective /ɪˈlɒdʒ.ɪ.kəl/

Illogical

非論理的
Meaning
not reasonable or sensible; lacking logic
Example
It would be illogical to go swimming in such cold weather.
こんなに寒い天気で泳ぐのは非論理的です。
C1 noun /ˌɪntərˌɒpərəˈbɪləti/

interoperability

相互運用性
Meaning
The ability of computer systems or software to exchange and make use of information.
Example
The interoperability of different software systems ensures seamless workflow.
異なるソフトウェアシステムの相互運用性は、シームレスな作業の流れを確保します。
C1 verb /ɪnˈfjʊərieɪt/

infuriate

激怒させる
Meaning
To make someone extremely angry.
Example
His careless remarks infuriated the entire team.
彼の不注意な発言がチーム全体を怒らせた。
C1 noun /ˌɪndɪɡˈneɪʃən/

indignation

憤慨
Meaning
Strong displeasure or anger caused by something unjust, offensive, or insulting.
Example
Public indignation grew after the unfair verdict.
不公平な判決の後で、公衆の憤慨が高まった。
C1 verb /ˌɪntərˈsɛpt/

intercept

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.
C1 adjective /ɪmˈplɔːzəbl/

implausible

信じがたい
Meaning
Not seeming reasonable or probable; unlikely to be true.
Example
The story she told was so implausible that no one believed her.
彼女が話した話はあまりにも信じられないほどで、誰も彼女を信じなかった。
C1 noun /ˈɪtʃ.i.nəs/

itchiness

かゆみ
Meaning
The quality or condition of feeling an irritating sensation on the skin that causes a desire to scratch.
Example
Eye itchiness often leads to rubbing.
目のかゆみはしばしば擦る原因となります。
C1 adjective /ɪnˈvɪnsəbl/

invincible

無敵
Meaning
too powerful to be defeated or overcome
Example
The team seemed invincible after winning ten matches in a row.
そのチームは10試合連続で勝利した後、無敵に見えた。
C1 adjective /ɪnˈstɪŋk.tɪv/

instinctive

本能的, 自然な, 自動的
Meaning
Based on instinct; done without conscious thought; natural and automatic.
Example
His instinctive reaction saved his life.
彼の本能的な反応は彼の命を救った。
C1 verb /ɪˈluːmɪneɪt/

illuminate

照らす
Meaning
To light up or make something clearer.
Example
Streetlights illuminate the road at night.
街路灯が夜に道路を照らします。
C1 adjective, noun /ˈɪnvəlɪd/ (adjective), /ɪnˈvælɪd/ (noun)

invalid

無効
Meaning
Not valid; having no force or effect. Also refers to a person too weak or ill to care for themselves.
Example
The court declared the contract invalid.
裁判所は契約を無効と宣言した。
C1 adjective /ˌɪnkənˈkluːsɪv/

inconclusive

結論が出ていない
Meaning
Not leading to a definite result or decision.
Example
The investigation remained inconclusive due to a lack of evidence.
証拠の不足により、調査は結論が出ていないままでした。
C1 adjective /ɪˈnɒkjuəs/

innocuous

無害な
Meaning
Not harmful or offensive.
Example
His remark was completely innocuous and not meant to offend anyone.
彼の発言は完全に無害で、誰かを傷つける意図はなかった。
C1 adjective /ˈaɪərnˌklæd/

ironclad

鉄壁の
Meaning
impossible to change, break, or dispute; very strong and firm
Example
The company had an ironclad contract with its suppliers.
その会社はサプライヤーと鉄壁の契約を結んでいた。