incandescence
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C2 noun /ˌɪnkænˈdɛsəns/

incandescence

白熱光
Meaning
the emission of light from a hot object; brilliance
Example
The incandescence of the candle filled the dark room.
ろうそくの白熱光が暗い部屋を満たしました。
C2 adjective /ˈɪnˌbrɛd/

inbred

生まれつき
Meaning
existing naturally in a person or animal; also related to reproduction within a limited community
Example
He has an inbred sense of loyalty.
彼には生まれつきの忠誠心があります。
C2 adjective /ˌɪnɔːˈspɪʃəs/

Inauspicious

不吉
Meaning
unlucky; showing signs that future success is unlikely; unfavorable
Example
The dark clouds seemed inauspicious for the wedding.
暗い雲は結婚式にとって不吉に思えた。
C2 adjective /ˌɪnˌɑːpərˈtuːn/

inopportune

タイミングが悪い瞬間
Meaning
Happening at a bad or inconvenient time.
Example
His call came at the most inopportune moment.
彼の電話は最もタイミングが悪い瞬間にかかってきた。
C2 noun /ˌɪn.strəˈmɛn.təl.ɪst/

instrumentalist

楽器奏者
Meaning
A person who plays a musical instrument.
Example
The instrumentalist played a beautiful solo on the violin.
楽器奏者はバイオリンで美しいソロを演奏しました。
C2 noun /ɪmˈpʌlʃən/

impulsion

Meaning
a strong urge or drive to act; the act of impelling
Example
His impulsion to travel made him leave his job suddenly.
C2 conjunction /ˌɪnəzˈmʌtʃ æz/

inasmuch-as

なぜなら
Meaning
Because; since.
Example
He cannot attend, inasmuch as he is unwell.
彼は出席できません、なぜなら彼は病気だからです。
C2 adjective /ˌɪnkænˈdɛsənt/

incandescent

白熱
Meaning
emitting light as a result of being heated; extremely bright or passionate
Example
The incandescent lamp lit up the entire hall.
白熱灯はホール全体を照らしました。
C2 adjective /ˌɪrɪˈprəʊtʃəbl̩/

irreproachable

非の打ち所がない
Meaning
Beyond criticism; faultless.
Example
The judge was known for his irreproachable integrity.
その裁判官は非の打ち所がない誠実さで知られていた。
C2 noun /ɪnˈkwɪzɪtər/

inquisitor

尋問者
Meaning
A person who asks many questions, often in an official or harsh manner.
Example
The inquisitor demanded detailed answers from the witness.
尋問者は証人から詳細な回答を要求しました。
C2 verb /ɪnˈtɜːr/

inter

埋葬する
Meaning
To bury a dead body in the ground.
Example
They decided to inter the soldier with full honors.
彼らは兵士を全ての名誉を持って埋葬することに決めた。
C2 noun /ˈɪn.fɪ.del/

Infidel

異教徒
Meaning
a person who does not believe in religion or whose religious beliefs differ from one's own
Example
In historical contexts, crusaders often referred to their enemies as infidels.
歴史的な文脈では、十字軍はしばしば自分たちの敵を異教徒と呼んでいました。
C2 adjective /ˌɪnɪkˈstɛnsəbl/

inextensible

伸縮不可
Meaning
Not capable of being stretched or extended.
Example
This rope is made of an inextensible material.
このロープは伸縮不可の材料でできています。
C2 noun /ˌɪnkænˈteɪʃən/

incantation

呪文
Meaning
a series of words used as a magic spell or charm
Example
The wizard chanted an incantation to summon the spirits.
魔法使いは霊を呼び出すために呪文を唱えました。
C2 noun /ɪnˈɡrætɪˌtjuːd/

ingratitude

恩知らず
Meaning
Lack of gratitude; failure to show thanks or appreciation.
Example
His ingratitude hurt her feelings after all she had done for him.
彼の恩知らずは、彼女が彼のために多くのことをした後、彼女の気持ちを傷つけた。
C2 adjective /ˌɪnɪkˈspiːdiənt/

inexpedient

不適切
Meaning
Not advisable, suitable, or practical in the circumstances.
Example
It would be inexpedient to invest without proper research.
適切な調査なしで投資することは不適切です。
C2 noun /ˈɪnroʊd/

inroad

進展
Meaning
An advance or significant progress, often at the expense of something else.
Example
The company made significant inroads into the mobile market.
その会社はモバイル市場で重要な進展を遂げました。
C2 noun /ˈɪrɪɡənt/

irrigant

灌漑液
Meaning
A liquid used for irrigation, especially in medical or agricultural contexts.
Example
The doctor used a sterile irrigant during the procedure.
医師は手術中に無菌の灌漑液を使用しました。
C2 adjective /ɪˈrɛzəluːt/

irresolute

優柔不断
Meaning
uncertain or indecisive; lacking determination
Example
He stood irresolute at the crossroads, unsure which path to take.
彼は交差点で優柔不断に立ち、どの道を取るべきか決められなかった。
C2 noun /ɪnˈtɛstəsi/

intestacy

遺言なしで死亡
Meaning
The condition of dying without having made a valid will.
Example
His estate was divided according to the laws of intestacy.
彼の財産は遺言なしでの法則に従って分けられた。
C2 adjective /ɪnˈsɛndiˌɛri/

incendiary

扇動的な / 挑発的な
Meaning
designed to cause fires or stir up conflict
Example
The politician’s incendiary remarks angered the crowd.
政治家の挑発的な発言が群衆を怒らせた。
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。
C2 adjective /ɪnˈdʒɛnjuəs/

ingenuous

無邪気
Meaning
Innocent, naive, and unsuspecting; showing childlike simplicity and sincerity.
Example
Her ingenuous smile revealed her genuine kindness.
彼女の無邪気な笑顔は彼女の本当の優しさを明らかにしました。
C2 adjective /ɪmˈpælpəbəl/

impalpable

触れない
Meaning
unable to be felt by touch; difficult to grasp or understand
Example
There was an impalpable sense of fear in the room.
部屋には触れない恐怖感があった。
C2 adjective /ɪnˈvaɪələt/

inviolate

汚されていない
Meaning
free from violation, injury, or desecration; kept safe and untouched
Example
The ancient temple remained inviolate for centuries.
古代の寺院は何世紀にもわたって汚されることなく保たれました。
C2 noun /ˈɪmɪˌteɪtər/

imitator

模倣者
Meaning
a person who copies the behavior, style, or actions of others
Example
He became famous as an imitator of popular singers.
彼は人気のある歌手の模倣者として有名になった。
C2 noun /ɪˈnænɪti/

inanity

馬鹿げたこと, 空虚
Meaning
a nonsensical remark or action; silliness; emptiness
Example
The speech was full of inanities that bored the audience.
スピーチは聴衆を退屈させる馬鹿げたことだらけだった。
C2 noun /ˌɪkθiˈɒlədʒi/

ichthyology

魚類学
Meaning
The branch of zoology that deals with fish.
Example
He pursued a degree in ichthyology at the university.
彼は大学で魚類学の学位を取得した。
C2 adverb /ˈaɪsɪli/

icily

冷たく
Meaning
In a very cold, unfriendly, or hostile manner.
Example
She replied icily to his question.
彼女は冷たく彼の質問に答えた。
C2 adjective /ˌɪnkənˈsɪdərəbl/

inconsiderable

取るに足らない
Meaning
Too small or unimportant to be worth considering.
Example
The donation was not inconsiderable, though smaller than expected.
寄付は取るに足らなかったが、予想よりも小さかった。
C2 noun /ˌɪnsəˈrɛkʃən/

insurrection

反乱
Meaning
A violent uprising against an authority or government.
Example
The army was called in to suppress the insurrection.
軍隊は反乱を鎮圧するために呼ばれました。
C2 adjective /ˈɪn.dɪ.dʒənt/

indigent

困窮
Meaning
lacking the necessities of life due to poverty; very poor
Example
The hospital offers free care to indigent patients.
病院は困窮した患者に無料でケアを提供しています。
C2 noun /ˈɪl.i.æd/

iliad

イリアス
Meaning
An ancient Greek epic poem attributed to Homer, describing the events of the Trojan War.
Example
Students studied the Iliad to understand Greek mythology and heroism.
学生たちはイリアスを学び、ギリシャ神話と英雄主義を理解しました。
C2 verb /ɪˈniː.bri.eɪt/

inebriate

Meaning
to intoxicate; to make someone drunk
Example
The strong wine was enough to inebriate even the most experienced drinker.
C2 noun /ɪnˈsuːsiəns/

insouciance

無関心
Meaning
Casual lack of concern; indifference.
Example
She carried herself with an air of insouciance, unbothered by the challenges ahead.
彼女は無関心な態度で歩いていた、前にある挑戦を気にせずに。
C2 noun /ɪmˈprɑːvɪdəns/

improvidence

不注意
Meaning
Lack of foresight or care for future needs.
Example
His improvidence led to financial difficulties.
彼の不注意が彼を財政的な困難に追い込んだ。
C2 adjective /ɪnˈvʌlnərəbl/

invulnerable

無敵
Meaning
Impossible to harm, damage, or defeat.
Example
The fortress was thought to be invulnerable to attack.
その要塞は攻撃に対して無敵だと考えられていた。
C2 adverb /ˈɪntʃmiːl/

inchmeal

少しずつ
Meaning
Gradually, little by little.
Example
The old castle fell inchmeal into ruin.
その古い城は少しずつ廃墟になった。
C2 adverb /ˌɪnsəʊˈmʌtʃ/

insomuch

これほど
Meaning
to such an extent
Example
He was insomuch tired that he could hardly stand.
彼はあまりにも疲れていて、ほとんど立つことができませんでした。
C2 noun /ɪnˈtɜːrstɪs/

interstice

隙間
Meaning
a small space that lies between things
Example
Light filtered through the narrow interstices of the wall.
光は壁の狭い隙間を通して漏れた。
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。
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 verb /ɪnˈsɪnəˌreɪt/

incinerate

焼却する
Meaning
to burn something completely until it is reduced to ashes
Example
The city decided to incinerate the medical waste for safety.
その都市は安全のために医療廃棄物を焼却することを決定しました。
C2 noun /ˈɪnsələns/

insolence

無礼
Meaning
rude or disrespectful behavior
Example
The teacher was shocked by the student's insolence.
教師は学生の無礼に驚きました。
C2 noun /ˌɪnˌkeɪpəˈbɪləti/

incapability

無能力
Meaning
lack of ability or power to do something; inability or incompetence
Example
His incapability to manage the team led to serious problems.
チームを管理する彼の無能力は深刻な問題を引き起こした。
C2 verb /ˌɪmpɔːrˈtuːn/

importune

しつこく頼む
Meaning
To ask someone persistently or pressingly for something
Example
The child importuned his mother for a new toy.
その子供は新しいおもちゃを欲しがって母親にしつこく頼んだ。
C2 noun /ɪnˈfriːkwəns/

infrequence

稀少性
Meaning
The state of occurring rarely or at long intervals.
Example
The infrequence of their meetings made it hard to maintain close ties.
彼らの会議の稀少性は、親密な関係を維持するのを難しくしていました。
C2 adjective /ˌɪnɪˈsɛnʃəl/

inessential

本質的でない
Meaning
not necessary or important; not essential
Example
The report removes all inessential details to stay focused.
その報告書は焦点を保つために本質的でない詳細を削除している。
C2 noun /ɪnˈtɛɡ.jʊ.mənt/

integument

外皮
Meaning
A natural outer covering, such as skin, shell, or rind.
Example
The snake sheds its integument as it grows.
ヘビは成長するにつれて外皮を脱ぎます。
C2 noun /ˌɪmbəˈsɪləti/

imbecility

愚かさ
Meaning
Extreme foolishness, stupidity, or weakness of mind.
Example
The plan was abandoned due to its sheer imbecility.
その計画はその愚かさから放棄されました。
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。
C2 noun /ɪmˈpjuːnɪti/

impunity

Meaning
freedom from punishment or harmful consequences for an action
Example
The dictator ruled with impunity, ignoring international laws.
C2 adjective ɪnˈfiː.zə.bəl

infeasible

不可能
Meaning
Not possible to do easily or conveniently; impracticable.
Example
Restoring the forest may become infeasible if destruction continues.
森林の回復は、破壊が続くと不可能になる可能性があります。
C2 noun /ˈaɪsinəs/

iciness

冷たさ
Meaning
The state of being cold in manner or temperature.
Example
There was a distinct iciness in his voice.
彼の声には明確な冷たさがあった。
C2 adjective /ˌɪnsəˈluːbriəs/

insalubrious

不健康
Meaning
Unhealthy or not conducive to well-being.
Example
They moved out of the insalubrious neighborhood for the sake of their health.
彼らは健康のために不健康な地域から引っ越しました
C2 adjective /ˌɪm.pəˈfɛk.tə.bəl/

imperfectible

インパーフェクティブル
Meaning
Incapable of being made perfect or complete.
Example
Some human qualities are considered imperfectible.
いくつかの人間の資質は、完璧にはならないと見なされます。
C2 adjective /ɪnˈæpt/

Inapt

不適切; 不適当
Meaning
not suitable; inappropriate; unfit
Example
His comment was inapt for the formal meeting.
彼のコメントは正式な会議には不適切でした。
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。
C2 verb /ɜːrk/

irk

苛立たせる
Meaning
to annoy or irritate someone
Example
It irks me when people are late without calling.
人々が電話をかけずに遅れると、私はイライラします。
C2 adjective /ɪnˈsɪpɪd/

insipid

味気ない
Meaning
lacking flavor, interest, or excitement; dull
Example
The soup was insipid and needed more seasoning.
スープは味気なく、もっと調味料が必要でした。
C2 noun /ɪˈluːmɪnənt/

illuminant

光源
Meaning
A substance or device that produces light.
Example
The lamp acted as an illuminant in the dark cave.
ランプは暗い洞窟で光源として機能しました。
C2 noun /ˈɪd.i.ə.si/

Idiocy

愚かさ
Meaning
extremely stupid behavior or actions; foolishness
Example
The decision to ignore safety protocols was pure idiocy that endangered everyone.
安全プロトコルを無視する決定は、すべての人を危険にさらす純粋な愚かさでした。
C2 verb /ɪnˈhjuːm/

inhume

埋葬する
Meaning
to bury a dead body in the ground
Example
They inhumed the warrior with full honors.
彼らは戦士を完全な名誉を持って埋葬しました。
C2 adjective /ˌɪrɪˈtriːvəbl/

irretrievable

回復不可能
Meaning
impossible to recover or regain
Example
The documents were lost in an irretrievable way after the fire.
火事の後、文書は回復不可能な方法で失われました。
C2 adjective /ɪnˈtɛsteɪt/

intestate

遺言なしで死亡
Meaning
Having died without leaving a valid will.
Example
She died intestate, so her assets were distributed by law.
彼女は遺言なしで死亡したため、財産は法に従って分配されました。
C2 adjective /aɪˈsɒ.krə.nəs/

isochronous

等時間間隔で発生する
Meaning
Occurring at equal time intervals; in unison or synchrony.
Example
The pendulum swings are isochronous, repeating at equal intervals.
振り子の動きは等時性があり、等しい間隔で繰り返されます。
C2 noun /ɪnˈdɛntʃər/

indenture

Meaning
A formal legal agreement, contract, or document, often relating to work or service.
Example
In the 18th century, many workers came under indenture to work overseas.
C2 verb /ɪnˈɡreɪʃiˌeɪt/

ingratiate

Meaning
To gain favor or approval by deliberate effort, often in a flattering way.
Example
She tried to ingratiate herself with her boss by complimenting him often.
C2 adjective /ɪˈnɪmɪkəl/

inimical

敵対的 / 不利な
Meaning
tending to obstruct or harm; unfriendly or hostile
Example
The policy was inimical to the country's economic growth.
その政策は国の経済成長に不利だった。
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。
C2 noun /ɪnˈtɜːrmənt/

interment

埋葬
Meaning
The act of burying a dead body in a grave or tomb.
Example
The interment took place at the family cemetery.
埋葬は家族の墓地で行われました。
C2 noun /ˌɪdiəˈsɪŋkrəsi/

idiosyncrasy

特異性
Meaning
A distinctive or peculiar characteristic, habit, or mannerism unique to an individual.
Example
One of her idiosyncrasies was humming while working.
彼女の一つの特異性は、仕事中に口ずさむことでした。
C2 noun /ˌaɪ.diˈeɪ.ʃən/

ideation

アイデア創出
Meaning
The process of forming and developing new ideas or concepts through creative thinking and brainstorming.
Example
The team engaged in ideation sessions to generate new product ideas.
チームは新製品のアイデアを生み出すためにアイデーションセッションに取り組んだ。
C2 adjective /ˌaɪsəʊˈθɜːrməl/

isothermal

等温
Meaning
Having or maintaining equal or constant temperature.
Example
The experiment was conducted under isothermal conditions.
実験は等温条件で行われました。
C2 adjective /ˌɪndɪˈfætɪɡəbl̩/

indefatigable

疲れ知らず
Meaning
persisting tirelessly; incapable of being fatigued
Example
Her indefatigable spirit kept the team motivated during the long project.
彼女の疲れ知らずの精神が、長いプロジェクトを通してチームを励ましました。
C2 noun /ɪnˈhɪərəns/

inherence

内在性
Meaning
The state of being an essential or permanent part of something.
Example
The inherence of risk is part of every business venture.
リスクの内在性はすべてのビジネス冒険の一部です。
C2 noun /ɪnˈɛrənsi/

inerrancy

無謬性
Meaning
the belief or quality of being free from error; absolute correctness
Example
Some religious groups strongly affirm the inerrancy of their sacred texts.
いくつかの宗教団体は、自分たちの聖典の誤りのなさを強く主張しています。
C2 noun /ˌɪnəməˈrɑːtə/

inamorata

Meaning
A woman with whom someone is in love; a female lover.
Example
He wrote a poem dedicated to his inamorata.
C2 adjective /ɪmˈpæsɪbəl/

impassible

無痛性
Meaning
Incapable of suffering or feeling pain (used mainly in theological or philosophical contexts).
Example
Some philosophers argue that God is impassible and cannot experience human emotions.
一部の哲学者は、神は無痛性であり、人間の感情を感じることはできないと主張しています。
C2 noun /ɪˌledʒ.əˈbɪl.ə.ti/

Illegibility

読みにくさ
Meaning
the quality of being impossible or difficult to read; unclear writing or print
Example
The doctor's handwriting was famous for its illegibility among the pharmacy staff.
医者の手書きは薬局のスタッフの間でその読みにくさで有名でした。
C2 adjective /ˈɪkθiɪk/

ichthyic

魚のような
Meaning
Relating to or resembling fish.
Example
The artist's painting had an ichthyic quality.
アーティストの絵には魚のような特徴がありました。
C2 adjective /ˌɪlˈneɪ.tʃəd/

ill-natured

性格が悪い
Meaning
Having a bad or unpleasant character; unkind or malicious.
Example
He made an ill-natured remark about his colleague.
彼は同僚について悪意のある発言をしました。
C2 noun /ˌɪlɪbəˈræləti/

illiberality

不寛容
Meaning
The quality of being illiberal; lack of tolerance or generosity.
Example
The illiberality of the new laws alarmed the citizens.
新しい法律の不寛容が市民を驚かせました。
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。
C2 noun /ˌɪn.ʌnˈdeɪ.ʃən/

inundation

洪水
Meaning
The act of flooding or overwhelming with water or things.
Example
The town suffered from a severe inundation after the heavy rains.
町は大雨後にひどい洪水に見舞われました。
C2 noun /aɪˈoʊtə/

iota

微小な量
Meaning
An extremely small amount.
Example
He did not show an iota of fear.
彼は恐怖の一片も見せませんでした。
C2 noun /ˌɪnədˈvɜːrtəns/

inadvertence

不注意
Meaning
Failure to pay attention; carelessness.
Example
The error happened through sheer inadvertence.
エラーは単なる不注意で発生しました。
C2 adjective /ɪmˈperɪʃəbəl/

Imperishable

不滅の; 永遠の; 朽ちない
Meaning
not subject to decay; lasting forever; eternal
Example
The imperishable beauty of classical art continues to inspire generations.
古典芸術の不滅の美しさは、世代を超えてインスピレーションを与え続けています。
C2 noun /ɪˈrʌp.ʃən/

Irruption

突然の暴力的な侵入; 侵略または襲撃; 突然の噴出または噴火
Meaning
a sudden violent entry; an invasion or raid; a sudden outburst or eruption
Example
The army's irruption into enemy territory caught the opposing forces completely off guard.
軍隊の敵領土へのイラプションは、相手の力を完全に不意を突いた。
C2 adjective /ɪˈnɪkwɪtəs/

iniquitous

不正義
Meaning
grossly unfair and morally wrong
Example
Slavery was one of the most iniquitous practices in history.
奴隷制は歴史上最も不正義な行為の一つでした。
C2 adjective /ˌɪnfəˈlɪsɪtəs/

infelicitous

不適切な
Meaning
not suitable or well chosen; awkward or unfortunate
Example
His infelicitous remark ruined the atmosphere of the meeting.
彼の不適切な発言は会議の雰囲気を台無しにしました。
C2 verb /ˈɪndjʊˌreɪt/

indurate

硬化する
Meaning
To harden or make something physically or emotionally tough.
Example
Years of hardship indurated his spirit.
長年の困難が彼の精神を鍛えました。
C2 verb /ˌɪntərˈpoʊz/

interpose

Meaning
To place or insert between one thing and another; to intervene in a situation.
Example
He quickly interposed himself between the fighters to stop the quarrel.
C2 adjective /ˌɪndɪˈtɜːrmənət/

indeterminate

不確定
Meaning
Not exactly known, defined, or established; vague or uncertain.
Example
The project was delayed for an indeterminate amount of time.
プロジェクトは不確定な期間に延期されました。
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 /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。
C2 adjective /ɪnˈtræn.sɪ.dʒənt/

intransigent

頑固な, 譲らない, 固執した
Meaning
Unwilling or refusing to change one's views or to agree about something.
Example
His intransigent stance delayed the agreement.
彼の頑固な態度が合意を遅らせました。
C2 noun /ɪnˌtɜːrpəˈleɪʃən/

interpolation

補間
Meaning
The act of inserting something into a text or estimating values within a sequence of data.
Example
The scientist used interpolation to predict the missing data points.
科学者は欠落したデータポイントを予測するために補間を使用しました。
C2 noun /ˌɪmpəˈtjuːəsəti/

impetuosity

衝動性
Meaning
The quality of being rash or impulsive.
Example
His impetuosity often got him into trouble.
彼の衝動性はしばしば彼を問題に巻き込んだ。
C2 adjective /ɪnˈskruːtəbl̩/

inscrutable

幸福
Meaning
impossible to understand or interpret
Example
His inscrutable expression made it hard to know what he was thinking.
彼女は賞を受け取ったとき、幸せを隠すことができませんでした。
C2 adjective /ˌɪn.trəˈmjʊə.rəl/

intramural

学内
Meaning
Occurring within the walls of a single institution, especially a school or college.
Example
The college organizes intramural sports competitions every semester.
大学は毎学期、学内スポーツ競技を開催しています。
C2 noun /ˌɪntərˈsɛsər/

intercessor

仲介者
Meaning
a person who intervenes or pleads on behalf of another
Example
He acted as an intercessor to resolve the conflict between the two families.
彼は二つの家族間の対立を解決するために仲介者として行動しました。
C2 adjective /ɪnhɑːrˈmoʊniəs/

Inharmonious

不協和音
Meaning
lacking harmony; discordant in sound; not in tune
Example
The inharmonious sounds from the broken piano made everyone cover their ears.
壊れたピアノからの不協和音がみんなを耳をふさがせました。
C2 verb /ɪnˈsteɪt/

instate

任命する
Meaning
To set up in position, office, or authority.
Example
The board decided to instate her as the new director.
取締役会は彼女を新しいディレクターにインステイトすることを決定しました。
C2 noun /ˈaɪ.ərn.wʊd/

Ironwood

アイアンウッド
Meaning
a hard, dense wood from various trees; also the tree itself that produces small flowers
Example
The ironwood tree blooms with tiny white flowers.
アイアンウッドの木は小さな白い花を咲かせます。
C2 adjective /ˌɪnkɔːrˈpɔːriəl/

incorporeal

無形
Meaning
lacking a physical body; not composed of matter; intangible
Example
Ghosts are often described as incorporeal beings.
ゴーストはしばしば無形の存在として描かれます。
C2 adjective /ˌɪn.ɪˈlʌk.tə.bəl/

ineluctable

Meaning
Impossible to avoid or escape; inevitable.
Example
Death is an ineluctable part of human existence.
C2 noun /ˈɪntərˌloʊpər/

interloper

干渉者
Meaning
A person who becomes involved in a situation or place where they are not wanted.
Example
He felt like an interloper at the private family gathering.
彼はプライベートな家族の集まりで干渉者のように感じた。
C2 adjective /ˈɪl bred/

Ill-bred

無作法な
Meaning
lacking good manners; rude; showing poor upbringing
Example
His ill-bred behavior shocked everyone at the dinner party.
彼の無作法な振る舞いは、ディナー・パーティーで皆を驚かせた。
C2 noun /ˌɪnsjəˈlærəti/

insularity

島国性
Meaning
The state of being isolated or narrow-minded.
Example
The insularity of the group prevented them from accepting new ideas.
グループの島国性は新しいアイデアを受け入れることを妨げた。
C2 verb /ˌɪn.trəˈmɪt/

intromit

挿入する
Meaning
To insert or introduce something into a place or body.
Example
The doctor carefully intromitted the instrument into the wound.
医者は慎重に器具を傷口に挿入しました。
C2 adjective /ɪmˈprɒvɪdənt/

improvident

先見の明がない
Meaning
Not having or showing foresight; spending wastefully or without thought for the future.
Example
His improvident habits left him with no savings.
彼の先見の明がない習慣は、貯金がないまま彼を残した。
C2 adjective /ˌɪnkəˈməʊdiəs/

incommodious

不快な
Meaning
Uncomfortably small, cramped, or inconvenient.
Example
We had to stay in an incommodious room during the trip.
旅行中に不快な部屋に泊まらなければなりませんでした。
C2 noun /ɪmˈpaɪ.ə.ti/

Impiety

不敬
Meaning
lack of piety or reverence, especially for a god; disrespect or irreverence toward religious matters
Example
His impiety shocked the religious community when he mocked their sacred ceremonies.
彼の不敬は、彼が彼らの神聖な儀式を嘲笑したとき、宗教コミュニティを驚かせました。
C2 verb /ɪnˈveɪ/

inveigh

激しく批判する
Meaning
To speak or write about something with great hostility and criticism.
Example
He inveighed against the corruption in government.
彼は政府の腐敗に対して激しく批判した。
C2 adjective /ɪnˈɡreɪʃiˌeɪtɪŋ/

ingratiating

お世辞を言う
Meaning
Charming or flattering in a way intended to gain favor.
Example
His ingratiating smile made everyone trust him quickly.
彼のお世辞を言う笑顔は、すべての人々に彼を素早く信頼させた。
C2 adjective /ˌɪnˈekspɜːrt/

inexpert

未熟な
Meaning
not skilled or experienced; lacking expertise
Example
The inexpert handling of the machine caused several mistakes.
機械の未熟な扱いがいくつかのミスを引き起こした。
C2 noun /ɪmˈpjuːɪsəns/

impuissance

無力, 無能
Meaning
inability to take effective action; helplessness
Example
The government’s impuissance in the face of crisis frustrated the people.
危機の前で政府の無力さが人々を失望させた。
C2 adjective /ɪnˈkɒntɪnənt/

incontinent

失禁
Meaning
lacking control over urination or defecation; lacking self-restraint
Example
The patient was incontinent after surgery.
手術後、患者は失禁していた。
C2 noun /ɪmˌpɜːrtərbəˈbɪləti/

imperturbability

不動心
Meaning
The quality of being calm and not easily disturbed or upset.
Example
Her imperturbability during the crisis impressed everyone.
危機の際に彼女の不動心は皆に印象を与えました。
C2 verb /ɪnˈtɜːrpəˌleɪt/

interpolate

挿入する
Meaning
To insert something, often words, into a text or conversation; to estimate values between known data points.
Example
The editor interpolated a missing paragraph into the manuscript.
編集者は原稿に欠落した段落を挿入した。