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C1 adjective /ˌɪndɪˈstɪŋkt/

indistinct

不明瞭な
Meaning
Not clear or sharply defined; vague or blurred.
Example
The sound of voices was indistinct in the distance.
遠くからの声は不明瞭でした。
C1 adverb /ɪnˈdɛfɪnətli/

indefinitely

無期限で
Meaning
for an unlimited or unspecified period of time
Example
The project has been postponed indefinitely.
プロジェクトは無期限で延期されました。
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。
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。
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 noun /ˌɪnˈdɪsəplɪn/

indiscipline

規律の欠如
Meaning
lack of discipline or self-control; failure to obey rules or maintain order
Example
Indiscipline among the students disrupted the learning environment.
学生の規律の欠如が学習環境を乱した。
C1 verb /ɪnˈdaɪt/

indict

起訴する
Meaning
to formally accuse someone of committing a serious crime
Example
The grand jury decided to indict the politician for corruption.
大陪審団は腐敗のために政治家を起訴することを決定した。
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。
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 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 noun ɪnˈdɪdʒɪnəs trəˈdɪʃənz

Indigenous Traditions

先住民の伝統
Meaning
Cultural practices, beliefs, and customs that have been passed down through generations among native peoples.
Example
Indigenous traditions in the Chittagong Hill Tracts are unique.
チッタゴン丘陵地帯の先住民の伝統はユニークです。
C1 adjective /ɪnˈsɒlvənt/

insolvent

破産
Meaning
unable to pay debts owed
Example
The insolvent firm could not meet its financial obligations.
破産した企業は財務義務を果たせなかった。
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 adjective /ˈɪnsjələr/

insular

狭い心の、島に関連する
Meaning
Narrow-minded, isolated, or relating to an island.
Example
The community was criticized for its insular attitudes toward outsiders.
そのコミュニティは外部の人々に対する狭量な態度で批判されました。
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。
C1 noun /ˌɪmɔːrˈtæləti/

immortality

不死; 永遠の命
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.
多くの古代文化では、英雄が偉業によって不死を得られると信じられていた。
C1 noun /aɪl/

isle

小さな島
Meaning
A small island or peninsula, often poetic or literary.
Example
They spent their honeymoon on a beautiful tropical isle.
彼らは美しい熱帯の島でハネムーンを過ごしました。
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。
C1 noun /ɪmˌpɒsəˈbɪlɪti/

impossibility

不可能性
Meaning
the state or fact of being impossible; something that cannot be done or achieved
Example
Finishing the project in one day was an impossibility.
一日でそのプロジェクトを終えるのは不可能だった。
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。
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 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 /ɪnˈtrɛpɪd/

intrepid

勇敢な
Meaning
fearless and adventurous, often used humorously
Example
The intrepid traveler explored the jungle alone.
その勇敢な旅行者は一人でジャングルを探検した。
C1 noun /ɪnˈfjuːʒən/

infusion

注入
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.
彼女はカモミールティーの落ち着く注入を準備しました。
C1 noun ˈɪn.fər.əns

inference

推論
Meaning
A conclusion reached on the basis of evidence and reasoning; logical deduction.
Example
Scientists make inferences based on experimental data.
科学者たちは実験データに基づいて推論を行います。
C1 adjective /ɪnˈɔːdəbl/

inaudible

聞こえない
Meaning
Unable to be heard.
Example
Her voice was almost inaudible over the noise.
その音の中で彼女の声はほとんど聞こえなかった。
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 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 /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 adjective /ɪnˈkɒŋɡruəs/

incongruous

不調和
Meaning
Not fitting in with or suitable for the surroundings.
Example
His jokes were incongruous during the serious meeting.
彼の冗談は真面目な会議では不調和だった。
C1 adjective /ɪˈmjuː.tə.bəl/

immutable

不変の
Meaning
Unchangeable, permanent, or fixed
Example
The laws of physics are considered immutable.
物理法則は不変と見なされます。
C1 noun /ɪnˈdɪɡ.nə.ti/

Indignity

屈辱
Meaning
treatment or circumstances that cause one to feel shame or loss of dignity; humiliation
Example
She refused to suffer the indignity of being searched without proper cause.
彼女は正当な理由もなく荷物検査を受けるという屈辱に耐えることを拒んだ。
C1 adverb /ˌɪn.ədˈvɜːr.tənt.li/

Inadvertently

うっかり; ついうっかり; 誤って
Meaning
without being aware of what you are doing; unintentionally; by mistake
Example
She inadvertently deleted the important file while cleaning her computer.
彼女はコンピュータを掃除しているとき、重要なファイルをうっかり削除してしまった。
C1 noun /ɪˈnɜː.ʃə/

Inertia

慣性; 活動の欠如
Meaning
a tendency to do nothing or remain unchanged; lack of activity or movement
Example
The team's inertia prevented them from adapting to the rapidly changing market conditions.
チームの慣性は、急速に変化する市場の状況に適応するのを妨げました。
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 verb ɪˈnɔː.ɡjə.reɪ.tɪd

inaugurated

開会
Meaning
Begin or introduce (a system, policy, or period) formally.
Example
The organization was inaugurated officially.
その組織は正式に開会されました。
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 /ˌɪnkəmˈpliːtnəs/

incompleteness

不完全さ
Meaning
the state of not being complete or whole; lack of necessary parts or fullness
Example
The incompleteness of the report caused delays in the project.
レポートの不完全さがプロジェクトの遅れを引き起こした。
C1 noun ɪnˈdʌldʒəns

indulgence

嗜好
Meaning
The practice of allowing oneself to enjoy the pleasure of something.
Example
His indulgence in junk food affected his health.
彼のジャンクフードへの過度の嗜好は健康を害した。
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。
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 adjective /ˌɪn.səˈbɔːr.dɪ.nət/

insubordinate

命令不服従
Meaning
Defiant of authority; disobedient to orders.
Example
The insubordinate employee refused to follow the manager's instructions.
命令不服従の従業員は、マネージャーの指示に従うことを拒否した。
C1 adjective /ɪˈrɛpərəbəl/

Irreparable

修復不可能
Meaning
impossible to repair or fix; permanent damage that cannot be undone
Example
The accident caused irreparable damage to his spine.
その事故は彼の背骨に修復不可能な損傷を与えました。
C1 adjective /ˌɪnkəʊˈhɪərənt/

incoherent

一貫性のない
Meaning
Not clear or easy to understand; lacking logical connection.
Example
His explanation was so incoherent that nobody could follow it.
彼の説明はあまりにも一貫性がなく、誰もそれを追うことができませんでした。
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 verb /ɪmˈpiːtʃ/

impeach

Meaning
To charge a public official with misconduct while in office.
Example
The parliament voted to impeach the president.
C1 verb /ɪnˈfjuːz/

infuse

Meaning
to fill or spread through something; to instill a quality, idea, or feeling
Example
The teacher tried to infuse her students with a love for reading.
C1 adjective /ˌɪlɪˈdʒɪtɪmət/

illegitimate

不正
Meaning
Not authorized by law, rules, or standards; not recognized as valid.
Example
The court ruled the contract to be illegitimate.
裁判所は契約が不正であると判断しました。
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 noun /ɪnˈfɜː.mə.ti/

Infirmity

虚弱; 病気; 衰弱
Meaning
physical or mental weakness; a disease or ailment; frailty
Example
Despite his advanced age and various infirmities, he remained mentally sharp and alert.
高齢で多くの病気を抱えていても、彼は精神的に鋭く、警戒心を持ち続けました。
C1 adjective /ˌaɪdiəˈlɪstɪk/

Idealistic

理想主義的
Meaning
pursuing high principles or ideals; unrealistically optimistic
Example
She has an idealistic view of changing the world.
彼女は世界を変えるという理想主義的な見方を持っています。
C1 adjective /ɪˈneɪn/

inane

無意味な, 馬鹿な
Meaning
lacking sense, meaning, or significance; silly or pointless
Example
The movie was criticized for its inane dialogue.
その映画は無意味なセリフで批判された。
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 /ˌɪndɪˈskriːt/

indiscreet

軽率
Meaning
Not careful in what one says or does, likely to reveal secrets or offend.
Example
It was indiscreet of him to mention the plan in public.
公衆の面前で計画について言及するのは軽率だった。
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。
C1 noun /ˌɪn.səˌbɔːr.dɪˈneɪ.ʃən/

insubordination

反抗
Meaning
Defiance of authority; refusal to obey orders.
Example
The soldier was punished for insubordination during the mission.
その兵士はミッション中の反抗で罰せられました。
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 verb /ɪnˈtɪmɪdeɪt/

intimidate

Meaning
To frighten or overawe someone, especially to make them do what one wants.
Example
The bully tried to intimidate the smaller kids.
C1 adjective /ɪnˈkɒmpɪtənt/

incompetent

Meaning
Lacking the necessary ability or skills to do something successfully.
Example
He was fired because he was incompetent at his job.
C1 noun /ɪmˈpjʊərəti/

impurity

不純物
Meaning
the state of being unclean or contaminated; a substance that makes something impure
Example
The scientist removed every impurity from the water sample.
科学者は水のサンプルからすべての不純物を取り除いた。
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 verb /ɪnˈsɪnjueɪt/

insinuate

Meaning
To suggest or hint something indirectly and often unpleasantly.
Example
He insinuated that she had lied about her qualifications.
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 /ɪˈlɪsɪt/

illicit

不法な
Meaning
Forbidden by law, rules, or custom.
Example
The police shut down the illicit drug operation.
警察は不法な麻薬取引を閉鎖しました。
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 /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 /ɪˈrɛfjʊtəbəl/

Irrefutable

反論できない
Meaning
impossible to deny or disprove; undeniable
Example
The evidence against him was irrefutable.
彼に対する証拠は否定できないものでした。
C1 adjective /ɪnˈɡreɪnd/

ingrained

根強い
Meaning
Firmly fixed or established; deeply rooted and difficult to change.
Example
His ingrained habits were hard to break.
彼の根強い習慣は壊すのが難しかった。
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 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 /ˈɪm.pæs/

impasse

行き詰まり
Meaning
A situation where no progress is possible.
Example
The negotiations reached an impasse, delaying the agreement.
交渉は行き詰まり、合意が遅れた。
C1 verb /ˌɪn.tɚˈtwaɪn/

intertwine

密接に接続またはリンクする; 一緒にねじるまたは密接に結合する
Meaning
To connect or link closely; to twist together or combine closely.
Example
Their lives became intertwined through years of friendship.
彼らの生活は長年の友情を通じて絡み合った。
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 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 verb /ɪɡˈnaɪt/

ignite

点火する
Meaning
To catch fire or cause to catch fire; to start or arouse.
Example
The sparks ignited the dry leaves in seconds.
火花が数秒で乾燥した葉に火をつけた。
C1 adjective ɪnˈsaɪ.sɪv

incisive

鋭い
Meaning
Intelligently analytical and clear-thinking; showing clear thought and good understanding of what is important.
Example
His incisive comments revealed the core issues.
彼の鋭いコメントは核心的な問題を明らかにしました。
C1 verb /ɪnˈtruːd/

intrude

干渉する
Meaning
To enter a place or situation where one is not wanted or not invited.
Example
He felt embarrassed to intrude on their private conversation.
彼は彼らのプライベートな会話に干渉して恥ずかしく思った。
C1 adjective /ɪˈræʃənəl/

irrational

非合理的
Meaning
not logical or reasonable; lacking clear thought
Example
His fear of the dark was completely irrational.
彼の暗闇への恐れは完全に非合理的でした。
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 noun /ɪnˌkɑːsəˈreɪʃən/

incarceration

投獄
Meaning
the state of being imprisoned or confined
Example
The criminal faced years of incarceration for his crimes.
犯人はその犯罪のために長年の投獄を受けた。
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。
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 /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 noun /ˌɪm.pəˈzɪʃ.ən/

Imposition

課税; 負担; 不公平な要求
Meaning
the action or process of imposing something or of being imposed; an unfair burden or demand
Example
The imposition of new taxes without consultation angered the citizens greatly.
相談なしに新しい税金が課され、市民は非常に怒りました。
C1 noun /ɪnˈsæn.ə.ti/

Insanity

狂気; 精神疾患
Meaning
the state of being seriously mentally ill; extreme foolishness or irrationality
Example
The defense lawyer argued that his client was not guilty by reason of insanity.
弁護人は、被告人が狂気によって無罪であると主張した。
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 /ˌɪndɪˈspjuːtəbəl/

Indisputable

議論の余地がない; 否定できない; 確定的
Meaning
impossible to deny or argue against; undeniable; certain
Example
The evidence against him was indisputable.
彼に対する証拠は議論の余地がなかった。
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 noun /ˌɪn.trəˈvɜːr.ʒən/

introversion

内向
Meaning
The tendency to be inward-looking and shy, preferring solitary activities.
Example
Her introversion made it difficult for her to enjoy large parties.
彼女の内向的な性格は、大きなパーティーを楽しむのを難しくした。
C1 adjective /ɪˈrɛvəkəbl/

irrevocable

取り消し不可能
Meaning
Not able to be revoked, changed, or undone.
Example
She made an irrevocable decision to leave the company.
彼女は会社を辞めるという取り消し不可能な決定を下した。
C1 adjective /ˌɪnəˈfɛnsɪv/

inoffensive

無害な
Meaning
Not likely to offend or provoke; harmless.
Example
His inoffensive remarks kept the conversation friendly.
彼の無害なコメントは会話を友好的に保ちました。
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 /ɪmˈpɛrɪl/

imperil

危険にさらす
Meaning
To put in danger or at risk.
Example
Reckless driving can imperil the lives of others.
無謀な運転は他人の命を危険にさらす可能性があります。
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。
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 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 noun /ɪnˈtruː.ʒən/

intrusion

不正侵入
Meaning
Unauthorized entry into a system or place without permission
Example
The company detected an intrusion in its server.
会社はサーバーに侵入を検出しました。
C1 noun /ɪnˈdem.nə.ti/

Indemnity

補償
Meaning
security or protection against a loss or other financial burden; compensation for damage or loss
Example
The insurance company provided full indemnity for the damages caused by the flood.
保険会社は洪水による損害に対して完全な補償を提供しました。
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 /ɪnˈædɪkwəsi/

inadequacy

不十分さ
Meaning
lack of sufficient ability, quality, or strength; a feeling of not being good enough
Example
She struggled with feelings of inadequacy at work despite her strong qualifications.
十分な資格があるにもかかわらず、彼女は職場で不十分さを感じていた。
C1 noun /ˌɪn.dɪˈsɪʒ.ən/

Indecision

優柔不断; 決断力の欠如; 迷い
Meaning
the inability to make decisions quickly; uncertainty about what to do
Example
Her indecision about which job offer to accept caused her to miss both opportunities.
どの仕事のオファーを受けるかについての優柔不断さが、両方のチャンスを逃す原因となった。
C1 adjective /ɪnˈdiːsənt/

indecent

不品な
Meaning
not conforming to accepted standards of behavior or morality; improper or offensive
Example
He was warned for making an indecent remark during the meeting.
彼は不品な発言で注意された。
C1 noun ˌɪnfɛsˈteɪʃən

infestation

侵入, 異常に大量の昆虫や動物がある場所に存在すること
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.
キッチンにおけるアリの侵入は、即座に害虫駆除対策を講じる結果となった。
C1 verb /ɪnˈkɑːrsəreɪt/

incarcerate

投獄する
Meaning
to imprison or confine someone
Example
The authorities incarcerated the criminal after the trial.
当局は裁判後に犯罪者を投獄しました。
C1 adjective /ˈɪnərmoʊst/

Innermost

最も深い; 最も個人的な
Meaning
most private and secret; deepest; most personal
Example
She shared her innermost feelings with her closest friend.
彼女は最も深い感情を最も親しい友人と共有しました。
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 adjective /ɪmˈpɛndɪŋ/

impending

差し迫った
Meaning
about to happen soon, usually something unpleasant or threatening
Example
The villagers were worried about the impending flood.
村人たちは差し迫った洪水を心配していた。
C1 noun /ˌɪnkɑːrˈneɪʃən/

incarnation

化身
Meaning
the embodiment of a deity, spirit, or quality in a physical form
Example
The monk was considered the incarnation of compassion.
その僧侶は慈悲の化身と見なされていた。
C1 noun /ˈaɪsətəʊp/

isotope

同位体
Meaning
Atoms of the same element with equal number of protons but different numbers of neutrons.
Example
Carbon-14 is a radioactive isotope used in dating fossils.
炭素-14は化石の年代を測定するために使用される放射性同位体です。
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 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 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 /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 adjective ˌɪn.təˈmɪt.ənt

intermittent

断続的
Meaning
Happening irregularly, not continuously.
Example
The rain was intermittent throughout the day.
雨は一日中断続的でした。
C1 noun /ˌɪntərˈmiːdiˌɛri/

intermediary

仲介者
Meaning
A person who acts as a link between people in order to try to bring about an agreement; a mediator.
Example
The diplomat served as an intermediary between the two conflicting nations.
外交官は二つの対立する国々の間で仲介者として機能した。
C1 noun /ɪˈreləvəns/

irrelevance

無関係性
Meaning
the quality of not being connected to or important for a particular matter; lack of significance
Example
His long explanation only highlighted the irrelevance of the details to the main issue.
彼の長い説明は、細部が主な問題と無関係であることを強調しただけだった。
C1 adjective /ɪnˈɛlɪdʒəbəl/

Ineligible

不適格; 無資格; 選ばれない
Meaning
not qualified or entitled to participate or be chosen; unsuitable
Example
Students with poor grades are ineligible for the scholarship program.
成績が悪い学生は奨学金プログラムに応募できません。
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 adjective /ɪnˈveə.ri.ə.bəl/

Invariable

不変の; 一定の; 常に同じ
Meaning
never changing; constant; always the same
Example
His invariable routine includes morning exercise and coffee.
彼の不変のルーチンには、朝の運動とコーヒーが含まれています。
C1 noun /ˈɪntrɪkəsi/

intricacy

複雑さ
Meaning
the quality of being very detailed or complicated
Example
The intricacy of the design impressed everyone.
デザインの複雑さは全員を感動させました。