invalid
All a b c d e f g h i j k l m n o p q r s t u v w x y z
All CEFR A1 A2 B1 B2 C1 C2
Content locale
EN 英語 BN ベンガル語 HI ヒンディー語 ES スペイン語 FR フランス語 DE ドイツ語 RU ロシア語 ZH 中国語 JA 日本語
All Vocabulary Cards All Vocabularies
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 /ɪmˈpoʊzɪŋ/

imposing

威圧的な
Meaning
having an appearance that is grand, impressive, or commanding
Example
The castle is an imposing structure overlooking the valley.
その城は谷を見下ろす威圧的な構造です。
C1 adjective /ɪnˈkrɛdjələs/

incredulous

Meaning
unwilling or unable to believe something
Example
He gave her an incredulous look when she claimed she could fly.
C1 verb ɪˈmɜːrs

immerse

浸る
Meaning
To involve oneself deeply in a particular activity or interest; to surround completely.
Example
Immerse yourself in the new language.
新しい言語に浸ってください。
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 adverb ɪnˈtrɪn.zɪ.kli

intrinsically

本質的に
Meaning
In a way that is naturally or inherently part of something's essential nature.
Example
Some people are intrinsically motivated to learn.
いくつかの人々は本質的に学ぶことに動機づけられている。
C1 verb ɪmˈbjuː

Imbue

誰かの心にアイデアや感情を深く浸透させる
Meaning
Mixing some idea or feeling deeply into someone's mind
Example
The teacher tried to imbue students with a love for learning.
教師は学生に学びへの愛を伝えようとした。
C2 noun /ɪmˈpruː.dəns/

Imprudence

無分別; 不注意; 軽率
Meaning
the quality of being imprudent; lack of care for consequences; recklessness
Example
His financial imprudence led to bankruptcy within just two years.
彼の財務の無分別は、わずか2年で破産を招いた。
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。
C2 noun /ˌɪnkəˈpæsəti/

incapacity

無能力
Meaning
the lack of ability, power, or fitness to do something
Example
His mental incapacity prevented him from making important decisions.
彼の精神的無能力は、重要な決定を下すのを妨げました。
A2 noun /ˈaɪtəm/

item

アイテム
Meaning
A single thing, object, or unit, often part of a list or collection.
Example
Each item on the list must be checked carefully.
リストの各アイテムは慎重にチェックする必要があります。
C1 noun /ˌɪntərˈmɪʃən/

intermission

休憩
Meaning
A pause or break, especially during a performance or event.
Example
The play had a twenty-minute intermission.
その劇には20分間の休憩がありました。
B2 noun /ˈɪnvənˌtɔːri/

inventory

インベントリ
Meaning
A complete list of items, such as goods in stock or property.
Example
The shopkeeper checked the inventory before opening the store.
店主は店を開店する前にインベントリを確認しました。
B1 verb /ɪnˈkriːst/

increased

増加した
Meaning
became greater in size, amount, or degree
Example
The company's revenue increased last year.
会社の収益は昨年増加しました。
C2 adjective /ɪnˈdjuːbɪtəbl/

indubitable

疑う余地がない
Meaning
Impossible to doubt; unquestionable.
Example
It is indubitable that hard work leads to success.
努力すれば成功に繋がることは疑う余地がない。
C2 verb ˈɪnʌndeɪt

inundate

洪水で満たす、処理すべき事柄や人々で誰かまたは何かを圧倒する
Meaning
To flood; overwhelm someone or something with things or people to be dealt with
Example
The company was inundated with requests after the advertisement.
広告の後、会社はリクエストで圧倒されました。
B2 noun, verb /ˈɪnstɪˌtjuːt/

institute

インスティチュート
Meaning
as a noun, an organization founded for a specific purpose; as a verb, to establish or initiate
Example
The university decided to institute new rules for the library.
大学は図書館のために新しいルールを設立することを決定しました。
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。
C2 verb /ɪmˈpjuːn/

impugn

Meaning
to dispute the truth, validity, or honesty of a statement or motive
Example
The lawyer tried to impugn the credibility of the witness.
B1 verb /ɪnˈsɪst/

insist

主張する
Meaning
to demand firmly; to state persistently
Example
He insisted on paying the bill.
彼は請求書の支払いを主張しました。
B1 noun /ɪnˈstrʌkʃənz/

instructions

指示
Meaning
Detailed information on how something should be done or operated.
Example
Please follow the instructions on the box.
箱に書かれた指示に従ってください。
B1 noun /ˈɪnpʊt/

input

入力、提供された情報
Meaning
information, advice, or data that is put into a system, device, or process
Example
The manager asked for everyone's input on the new project.
マネージャーは新しいプロジェクトに対する全員のインプットを求めました。
C2 noun /ˌɪkθiˈɒlədʒɪst/

ichthyologist

魚類学者
Meaning
A scientist who studies fish.
Example
The ichthyologist discovered a new species of fish in the river.
魚類学者は川で新しい魚の種を発見しました。
C1 noun /ɪnˈhɛrɪtər/

inheritor

相続人
Meaning
a person who receives money, property, or a title when someone dies
Example
She became the inheritor of her family's estate.
彼女は家族の財産の相続人となった。
B2 adjective /ɪnˈækjərət/

Inaccurate

不正確; 間違っている; 誤り
Meaning
not correct; containing errors; wrong
Example
The weather forecast was inaccurate yesterday.
昨日の天気予報は不正確でした。
B1 noun ˈɪn.də.stri

industry

産業
Meaning
Economic activity concerned with the processing of raw materials and manufacture of goods in factories.
Example
The industry focuses on luxury experiences.
産業は高級体験に焦点を合わせています。
C2 verb /ɪnˈdɒktrɪˌneɪt/

indoctrinate

教義を押し付ける
Meaning
To teach someone to fully accept a set of beliefs or ideas without question.
Example
The regime tried to indoctrinate the youth with propaganda.
その政権は宣伝を通じて若者を洗脳しようとした。
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。
B2 verb /ɪnˈflɪkt/

inflict

加える
Meaning
to cause something unpleasant or painful to be suffered by someone or something
Example
The storm inflicted considerable damage to the city.
嵐は都市にかなりの被害を与えました。
C2 noun /ˈɪn.tɪ.ɡreɪ.tɪv dɪˈpləʊ.mə.si/

integrative diplomacy

統合的外交
Meaning
A diplomatic approach that seeks to combine or coordinate different elements, interests, or parties into a unified whole.
Example
Integrative diplomacy strengthens alliances.
統合的外交は同盟を強化する。
C1 noun /ˌɪntəkəˈnɛktɪvɪti/

interconnectivity

相互接続性
Meaning
The state of being interconnected or the degree of connectivity between components
Example
The rise of interconnectivity has transformed global communication.
インターコネクティビティの発展は、世界中のコミュニケーションを変革しました。
B1 verb /ɪnˈvɛnt/

invent

発明する
Meaning
to create or design something that has not existed before
Example
Thomas Edison invented the electric bulb.
トーマス・エジソンは電球を発明しました。
A2 adjective, noun /ɪˈtæliən/

italian

幸福
Meaning
relating to Italy, its people, or its language; a person from Italy
Example
She loves Italian food.
彼女は賞を受け取ったとき、自分の幸せを隠せませんでした。
C1 adjective /ˈɪndɪɡoʊ bluː/

Indigo-blue

インディゴブルー
Meaning
a deep blue color with a purplish tinge
Example
The indigo-blue sky looked magnificent at twilight.
インディゴブルーの空は夕暮れ時に壮大に見えた。
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。
C2 adjective /ɪnˈkɒnstənt/

inconstant

不安定な
Meaning
frequently changing; not consistent or dependable
Example
His inconstant moods made it difficult to work with him.
彼の不安定な気分は彼と仕事をするのを難しくした。
C1 noun /ˌɪnkoʊˈhɪrəns/

incoherence

不整合
Meaning
The quality of being unclear, confused, or lacking logical connection.
Example
His speech was full of incoherence and difficult to follow.
彼のスピーチは不整合で、理解するのが難しかった。
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 adjective /ˌɪn.səbˈstæn.ʃəl/

insubstantial

不十分な
Meaning
Lacking strength, substance, or solidity.
Example
The evidence provided was insubstantial and unconvincing.
提供された証拠は不十分で説得力がなかった。
B2 noun ˈɪndɪkeɪtə

indicator

指標
Meaning
A thing that indicates the state or level of something.
Example
The unemployment rate is a key indicator of economic health.
失業率は経済の健康の重要な指標です。
C1 verb /ɪnˈfleɪt/

inflate

膨らませる；水増しする
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.
整備士はタイヤを適切な空気圧まで膨らませた。
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 noun ˌɪntədɪˈpɛndənsi

interdependency

相互依存
Meaning
The dependence of two or more people or things on each other.
Example
The interdependency of the countries led to greater cooperation.
国々の相互依存は、より大きな協力を生み出しました。
C1 noun ˌɪrɪˈvɜːrsəbl ˈdæmɪdʒ

irreversible damage

取り返しのつかない損害
Meaning
Harm or injury that cannot be undone or repaired.
Example
Climate change causes irreversible damage to ecosystems.
気候変動は生態系に取り返しのつかない損害を与えます。
C1 adjective /ɪˈledʒ.ə.bəl/

illegible

読めない
Meaning
Not clear enough to be read; unreadable.
Example
The doctor’s handwriting was almost illegible.
医者の手書きはほとんど読めなかった。
B1 adjective /ɪˈliː.ɡəl/

illegal

違法
Meaning
Not allowed by law; unlawful.
Example
It is illegal to drive without a valid license.
有効な免許なしで運転することは違法です。
A1 noun /aɪs/

Ice

氷
Meaning
water that has frozen and become solid
Example
The ice in my drink melted quickly in the hot weather.
私の飲み物の氷は暑い天気で素早く溶けました。
C1 verb /ɪmˈpɑːrt/

impart

伝える
Meaning
to make information known; to bestow or communicate
Example
The teacher imparted valuable knowledge to her students.
教師は生徒に貴重な知識を授けました。
B1 adverb /ɪnˈkriːsɪŋli/

increasingly

ますます
Meaning
more and more over time
Example
People are increasingly concerned about climate change.
人々は気候変動についてますます懸念しています。
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。
A2 adjective /ˈɪntrəstɪd/

interested

興味がある
Meaning
Showing curiosity or concern about something.
Example
She is very interested in learning new languages.
彼女は新しい言語を学ぶことにとても興味がある。
C2 adjective /ɪnˈsuːsiənt/

insouciant

無頓着
Meaning
Showing a casual lack of concern; carefree.
Example
He gave an insouciant shrug and walked away.
彼は無頓着に肩をすくめて、歩き去った。
B1 noun /ɪnˈstrʌktər/

instructor

インストラクター
Meaning
A person who teaches a subject or skill.
Example
The driving instructor was very patient with new learners.
運転インストラクターは新しい生徒にとても忍耐強かった。
C2 verb /ɪˈnjʊər/

inure

慣れる
Meaning
To become accustomed to something, especially something unpleasant.
Example
Soldiers quickly became inured to the harsh conditions.
兵士たちはすぐに過酷な状況に慣れました。
B2 verb /ˈaɪ.sə.leɪt/

isolate

隔離する
Meaning
To separate something or someone from others.
Example
Doctors tried to isolate the patient to prevent the spread of infection.
医師たちは感染の拡大を防ぐために患者を隔離しようとしました。
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。
A1 preposition /ɪn/

in

中
Meaning
expressing the situation of being enclosed or surrounded by something
Example
She is in the kitchen preparing dinner.
彼女は台所で夕食を準備している。
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 /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。
B2 adjective /aɪˈrɒnɪk/

ironic

皮肉な、風刺的な
Meaning
happening in the opposite way to what is expected, often amusing or sarcastic
Example
It is ironic that the fire station burned down.
消防署が焼けるのは皮肉です。
C1 adjective; noun /ɪˈmɔːrtl/

immortal

不死の
Meaning
living forever; never dying; lasting forever in fame or memory
Example
Legends often describe heroes as immortal beings who never die.
伝説では英雄は不死の存在だとされる。
C1 noun /ɪmˈpɛdɪmənt/

impediments

障害
Meaning
A hindrance or obstruction in doing something; things that prevent progress or achievement.
Example
Economic impediments often hinder social development.
経済的な障害はしばしば社会的発展を妨げる。
B2 noun ˌɪr.ɪˈɡeɪ.ʃən

irrigation

灌漑
Meaning
The artificial application of water to land or soil.
Example
Irrigation systems improve crop yields in dry regions.
灌漑システムは乾燥した地域で作物の収穫量を増加させます。
B2 adjective /ɪnˈsɛnsətɪv/

insensitive

無神経な
Meaning
Showing or feeling no concern for others' feelings.
Example
His insensitive comment hurt her deeply.
彼の無神経なコメントは彼女を深く傷つけました。
A2 noun /ˈɪʃ.uːz/

issues

問題
Meaning
Important topics or problems for debate or discussion.
Example
Health issues from pollution are increasing.
汚染による健康問題が増加しています。
C1 adjective /ˌɪnhɒˈspɪtəbl/

inhospitable

住みにくい
Meaning
Harsh and difficult to live in; unfriendly or unwelcoming to guests.
Example
The desert is an inhospitable environment for most plants.
砂漠はほとんどの植物にとって住みにくい環境です。
C2 adverb /ˌɪnəzˈmʌtʃ/

inasmuch

〜という点で
Meaning
To the extent that; considering that.
Example
Inasmuch as you are their teacher, you should guide them carefully.
あなたが彼らの教師である限り、彼らを慎重に指導するべきです。
C1 adjective /ɪnˈtræk.tə.bəl/

intractable

管理不能
Meaning
Difficult or impossible to manage, control, or solve.
Example
The conflict has become an intractable problem.
その対立は管理不能な問題になった。
C1 adjective /ɪnˈsɪstənt/

insistent

執拗な
Meaning
demanding something firmly and refusing to accept no
Example
The child was insistent on getting a new toy.
その子供は新しいおもちゃを手に入れることに執拗だった。
B2 noun /ˌɪntərˈsɛkʃən/

intersection

交差点
Meaning
a point where two or more things intersect, especially a road or path
Example
The intersection of Main Street and 5th Avenue is always busy.
メインストリートと5番街の交差点はいつも混んでいます。
C1 adjective /ɪnˈhɪbɪtɪd/

inhibited

抑制された
Meaning
Unable to act in a relaxed and natural way, especially due to self-consciousness or restraint.
Example
He was too inhibited to express his true feelings.
彼は自分の本当の感情を表現するにはあまりにも抑制されていた。
C2 adjective /ɪmˈpɑːlɪtɪk/

impolitic

無礼な
Meaning
Unwise or imprudent; not showing good judgment.
Example
It would be impolitic to criticize them openly.
彼らを公然と批判するのは無礼だろう。
C2 noun /ˌɪnvəˈluːʃən/

involution

インヴォリューション
Meaning
a complicated or intricate form or state; in biology, the shrinking of an organ after its function has finished
Example
The story was full of involution, making it hard to follow.
その話はインヴォリューションで満ちており、追うのが難しかった。
C2 noun /ˈɪndɪkənt/

indicant

指標
Meaning
Something that indicates or points to a fact or condition.
Example
High fever is often an indicant of infection.
高熱はしばしば感染の指標となります。
B2 adjective /ˌɪnsɪˈkjʊə/

insecure

不安定
Meaning
not confident or assured; uncertain and anxious
Example
She felt insecure about her performance in the exam.
彼女は試験での自分のパフォーマンスに不安を感じていました。
B2 adjective ˈɪn.tɪ.ɡreɪ.tɪd

integrated

統合された
Meaning
Combining or coordinating separate elements so as to provide a harmonious, interrelated whole.
Example
Integrated systems optimize efficiency.
統合されたシステムは効率を最適化します。
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。
C2 adjective /ˌɪrɪˈdɛsənt/

iridescent

虹色の
Meaning
showing luminous colors that seem to change when seen from different angles
Example
She wore an iridescent dress that sparkled in the light.
彼女は光の中で輝く虹色のドレスを着ていました。
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。
B1 adjective ˈɪnəveɪtɪv

innovative

革新的な
Meaning
Featuring new methods; advanced and original
Example
Innovative strategies are required to combat pollution.
革新的な戦略が汚染との戦いに必要です。
C2 noun /ɪˈnɪkwɪti/

iniquity

不正
Meaning
Immoral or grossly unfair behavior.
Example
The dictator's regime was marked by corruption and iniquity.
独裁者の政権は腐敗と不正で特徴づけられていました。
C2 adverb /ɪnˈdjuːbɪtəbli/

indubitably

疑いなく
Meaning
Without a doubt; certainly.
Example
She is indubitably the best candidate for the job.
彼女は疑いなくその仕事の最良の候補者です。
C1 noun /ˌɪnkəmˌpætəˈbɪlɪti/

incompatibility

非互換性
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.
2つのソフトウェアシステムの非互換性のため、そのプロジェクトは失敗した。
B1 noun ˈɪmpækt

impact

影響
Meaning
A strong effect or influence; the action of one object coming forcibly into contact with another.
Example
The decision had great impact.
その決定は大きな影響を与えた。
B2 verb ɪnˈvɛst.ɪŋ

investing

投資
Meaning
The act of putting money into financial schemes, shares, property, or a commercial venture with the expectation of achieving a profit.
Example
Investing in stocks can generate long-term wealth.
株式投資は長期的な富を生むことができます。
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。
C2 verb /ˈɪmprɪkeɪt/

imprecate

呪う
Meaning
To utter a curse or invoke evil upon someone.
Example
The old woman imprecated her enemies with dark words.
その年老いた女性は暗い言葉で敵を呪いました。
C1 adjective /ɪnˈdɪɡnənt/

indignant

憤慨した
Meaning
Feeling or showing anger at something considered unfair or unjust.
Example
She was indignant when accused of cheating.
彼女は不正行為を非難されたとき、憤慨していた。
C2 noun /ˈɪkθiəˌsɔːrz/

ichthyosaurs

イクチオサウルス（絶滅した海の爬虫類）
Meaning
Extinct marine reptiles that resembled fish and dolphins, dominant during the Mesozoic era.
Example
Ichthyosaurs were swift predators of the ancient seas.
イクチオサウルスは古代の海で素早い捕食者でした。
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 verb /ˈɪnkjʊˌbeɪt/

incubate

孵化する
Meaning
to keep eggs, cells, or organisms at the right conditions for development
Example
The hen will incubate the eggs until they hatch.
そのニワトリは卵が孵化するまでインキュベートします。
C2 adjective /ˌɪnkoʊˈɜːrsəbl̩/

incoercible

強制できない
Meaning
Not capable of being forced, compelled, or restrained.
Example
Her incoercible spirit inspired others to fight for justice.
彼女の強制できない精神は他の人々に正義のために戦うようにインスパイアした。
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。
B2 verb /ɪnˈfɜːr/

infer

Meaning
to conclude or deduce something from evidence and reasoning rather than from explicit statements
Example
From his silence, I inferred that he was not happy with the decision.
C1 adjective /ɪnˈdʌstriəs/

industrious

勤勉な
Meaning
Hardworking and diligent in one's duties.
Example
She is an industrious student who always completes her assignments on time.
彼女は常に期限通りに課題を終わらせる勤勉な学生です。
C2 noun /ˈaɪ.kɒn/

ikon

宗教的な画像やシンボル
Meaning
A religious image or symbol, especially in the Eastern Orthodox Church.
Example
The church displayed a beautifully painted ikon of the Virgin Mary.
教会は美しく描かれた聖母マリアのアイコンを展示しました。
C1 noun ˌɪm.pʌlˈsɪv.ɪ.ti

impulsivity

衝動性
Meaning
The tendency to act quickly and without thought or care; lack of self-control.
Example
His impulsivity led him to make reckless choices.
彼の衝動性は、無謀な選択をさせた。
C2 adjective /ɪˈmɪsəbl/

immiscible

不混和
Meaning
Describes liquids that do not mix together.
Example
Oil and water are immiscible liquids.
油と水は不混和の液体です。
B2 adjective + noun aɪˈdiːəl ɪnˈvaɪrənmənt

ideal environment

理想的な環境
Meaning
Perfect or most suitable conditions for growth or development
Example
Winter creates an ideal environment for vegetable growth.
冬は野菜の成長に理想的な環境を作り出します。
B2 verb /ɪnˈʃʊər/

insure

保険をかける
Meaning
to provide insurance; to make certain
Example
I need to insure my new car.
私は新しい車を保険に入れる必要があります。
C2 noun /ɪnˈtɒksɪkənt/

intoxicant

酔わせる物質
Meaning
a substance, especially alcohol or a drug, that causes intoxication
Example
Alcohol is the most commonly used intoxicant in many cultures.
アルコールは多くの文化で最も一般的に使用される酔わせる物質です。
C2 adjective /ˌɪrɪˈlɪdʒəs/

irreligious

無宗教
Meaning
Indifferent or hostile to religion
Example
Some people in the community consider him irreligious because he never attends religious services.
コミュニティの中で、彼は宗教的なサービスに一度も参加しないため、無宗教だと考えられています。
C1 adjective /ˌɪntərˈtʃeɪndʒəbl/

interchangeable

交換可能な
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.
これらの機械部品は交換可能なため、簡単に交換できます。
C2 verb ɪmˈbaɪb

imbibe

吸収する, 同化する, 飲む
Meaning
Absorb or assimilate ideas or knowledge. To drink or take in.
Example
He tried to imbibe the wisdom from his mentor.
彼は師匠から知恵を吸収しようとした。
C2 noun /ɪnˌtɛl.ɪˈdʒɛntsi.ə/

intelligentsia

インテリゲンチャ
Meaning
The group of people engaged in intellectual and cultural pursuits in a society.
Example
The intelligentsia played a key role in shaping public opinion.
インテリゲンチャは、世論形成において重要な役割を果たした。
C2 verb /ɪnˈfætʃueɪt/

infatuate

夢中にさせる
Meaning
to inspire with an intense but short-lived passion or admiration
Example
He was infatuated with her beauty.
彼は彼女の美しさに夢中でした。
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。
C2 adjective /ˌaɪ.kə.nəˈklæs.tɪk/

iconoclastic

確立された信念、伝統、または価値観に対して攻撃的または拒絶的な特徴
Meaning
Characterized by attacking or rejecting cherished beliefs, traditions, or established values.
Example
Her iconoclastic views challenged the conventional wisdom of the industry.
彼女のアイコノクラスティックな見解は業界の従来の知恵に挑戦した。
B2 adjective /ɪnˈdɪf.ər.ənt/

indifferent

無関心
Meaning
having no particular interest or concern; not caring one way or another
Example
She was indifferent to the outcome of the match.
彼女は試合の結果に無関心だった。
B2 noun ˌɪntəˈlektʃuəlz

intellectuals

知識人
Meaning
People possessing a highly developed intellect; scholars or academics.
Example
Intellectuals protested against the dominance.
知識人は支配に反対した。
C1 noun /ˈɪnstɪˌɡeɪtər/

instigator

扇動者
Meaning
A person who brings about or initiates something, usually something bad.
Example
The police identified him as the instigator of the violence.
警察は彼を暴力の扇動者として特定しました。
C1 adjective /ˈɪnsələnt/

insolent

無礼な、傲慢な
Meaning
showing a rude and arrogant lack of respect
Example
The insolent student refused to follow the teacher's instructions.
その無礼な学生は教師の指示に従うことを拒否した。
C1 adjective ɪnɪɡˈzɔːstɪbəl

inexhaustible

尽きることのない
Meaning
Unable to be used up or worn out; limitless.
Example
His inexhaustible energy allowed him to work tirelessly on his projects.
彼の尽きることのないエネルギーは、彼がプロジェクトに休むことなく取り組むことを可能にしました。
C2 adjective /ɪnˈɡlɔːriəs/

inglorious

不名誉な
Meaning
Causing shame or disgrace; not bringing honor or glory.
Example
The army suffered an inglorious defeat.
軍隊は不名誉な敗北を喫した。
C2 adjective /ɪˈlɪmɪtəbl/

illimitable

無限
Meaning
Without limits or bounds.
Example
The universe is often described as illimitable.
宇宙はしばしば無限であると説明されます。
C2 noun /ɪnˈvɛktɪv/

invective

侮辱的な言葉
Meaning
Insulting, abusive, or highly critical language.
Example
The politician’s speech was filled with invective against his opponents.
その政治家の演説は、対立候補に対する侮辱的な言葉で満ちていた。
C2 noun /ˌɪnkrɪˈdjuːləti/

incredulity

不信
Meaning
the state of being unwilling or unable to believe something
Example
She looked at him with incredulity after hearing the strange story.
彼女はその奇妙な話を聞いた後、不信のまなざしで彼を見つめた。
B2 verb /ɪnˈfɛkt/

infect

感染させる
Meaning
To contaminate with a disease-causing organism.
Example
The virus can infect healthy people quickly.
ウイルスは健康な人々を迅速に感染させることができます。
B2 verb /ˈɪr.ɪ.teɪt/

irritate

イライラさせる
Meaning
To make someone annoyed or angry; to cause discomfort or inflammation.
Example
Rubbing your eyes can irritate them.
目をこすると、それが刺激になることがあります。
C2 noun /ˌɪnvəˈkeɪʃən/

invocation

祈願
Meaning
the act of calling upon a higher power for help, blessing, or inspiration
Example
The ceremony began with an invocation to the gods.
儀式は神々への祈願から始まりました。
C2 noun /ˈaɪ.lət/

islet

小島
Meaning
A very small island.
Example
The fishermen rested on a tiny islet before continuing their journey.
漁師たちは旅を続ける前に小さな島で休憩しました。