irreversible
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 /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。
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。
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 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。
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。
B2 verb /ɪmˈpoʊzd/

imposed

課す
Meaning
forced something to be accepted or put in place
Example
The government imposed new regulations on the industry.
政府は産業に新しい規制を課した。
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 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。
B2 noun /ɪnˈtɛnt/

intent

意図
Meaning
the purpose or reason behind an action; a strong determination to do something
Example
Her intent was to improve the quality of education in the community.
彼女の意図はコミュニティの教育の質を向上させることでした。
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。
C2 noun /ɪmˌprɒb.əˈbɪl.ə.ti/

Improbability

不確実性
Meaning
the quality or state of being improbable; unlikely to be true or to happen
Example
The improbability of winning the lottery twice didn't stop her from buying tickets.
ロトで二回連続で当選する可能性の低さは、彼女がチケットを買うのを止めませんでした。
C2 noun /aɪˈdɒlətri/

idolatry

偶像崇拝
Meaning
The worship of idols or extreme admiration for someone or something.
Example
The priest condemned the idolatry practiced in the village.
司祭は村で行われている偶像崇拝を非難した。
B2 noun /ˈɪntərvəl/

interval

インターバル
Meaning
a period of time between two events or points; a pause or break in activity
Example
There was a short interval between the two performances.
二つの公演の間には短いインターバルがありました。
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。
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。
C1 adjective /ɪnˈvɑːlənˌtɛri/

involuntary

不随意
Meaning
done without will or conscious control
Example
He gave an involuntary shiver when he heard the loud noise.
彼は大きな音を聞いたとき、不随意に震えた。
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 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。
B2 verb /ɪnˈtɜːrprət/

interpret

Meaning
to explain the meaning of something; to translate orally
Example
She had to interpret the speech for the foreign guests.
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。
B1 adjective /aɪˈdiːəl/

ideal

理想的な
Meaning
the best possible; perfect for a situation
Example
This place is ideal for a picnic.
この場所はピクニックに理想的です。
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。
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 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。
B1 adjective ˌɪn.dɪˈpen.dənt

independent

独立
Meaning
Not depending on another for livelihood or subsistence; free from outside control; not subject to another's authority.
Example
An independent institution ensures transparency in governance.
独立した機関は、ガバナンスの透明性を保証します。
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 /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 adjective /ɪˈræsɪbl/

irascible

怒りっぽい
Meaning
Easily angered; quick-tempered.
Example
His irascible nature often got him into trouble.
彼の怒りっぽい性格はよくトラブルを引き起こしていた。
C1 verb /ˌɪnstɪˈtjuːʃənəlaɪz/

institutionalize

制度化する
Meaning
to establish something as a formal institution, custom, or practice
Example
The government seeks to institutionalize environmental protection.
政府は環境保護を制度化しようとしています。
C1 noun /ɪmˈprɪzənmənt/

imprisonment

投獄
Meaning
the act of putting someone in prison; the state of being confined as punishment
Example
He faced imprisonment for violating the court order.
彼は裁判所の命令に違反して投獄に直面した。
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 /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。
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。
A1 adjective /ɪmˈpɔː.tənt/

important

重要
Meaning
Of great significance or value; likely to have a profound effect on success, survival, or well-being.
Example
Important steps must be taken to address pollution.
汚染に対処するためには重要なステップを踏む必要があります。
C2 adjective /ɪmˈplaɪəbl/

impliable

暗示可能な
Meaning
Capable of being implied or suggested.
Example
The meaning of the statement is not directly clear but is impliable from the context.
その声明の意味は直接的には明確ではないが、文脈から推測可能である。
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。
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。
B2 adjective /ˌɪnsɪɡˈnɪfɪkənt/

insignificant

重要でない
Meaning
Too small or unimportant to be worth considering.
Example
The cost was so insignificant that nobody noticed it.
そのコストは重要でなく、誰もそれに気づかなかった。
C1 adjective /ɪˈnɔːrdənət/

inordinate

過度の
Meaning
Excessive or unusually large in degree.
Example
She spent an inordinate amount of time on her phone.
彼女は電話に過度の時間を費やしました。
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 /ɪnˈveɪsɪv/

invasive

侵襲的
Meaning
Tending to spread harmfully, intruding aggressively, or encroaching beyond proper boundaries.
Example
The doctor explained that the procedure was minimally invasive.
医者は、その手順が最小限の侵襲的であることを説明しました。
B2 noun ɪnˈsɛntɪvz

incentives

インセンティブ
Meaning
Things that motivate or encourage one to do something.
Example
Tax incentives are used to encourage investment in renewable energy.
税制上のインセンティブは再生可能エネルギーへの投資を促進するために使用されます。
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.
B2 verb /ɪmˈprɪzən/

imprison

投獄する
Meaning
to put someone in prison; to confine or restrict someone's freedom
Example
The judge imprisoned the criminal for five years.
裁判官は犯罪者を5年間投獄しました。
B2 adjective, noun /ɪzˈreɪli/

israeli

イスラエルの
Meaning
relating to Israel or its people; a person from Israel
Example
She works for an Israeli company.
彼女はイスラエルの会社で働いています。
C2 noun /ˌɪn.ɪˈbraɪ.ə.ti/

inebriety

酩酊
Meaning
the state of being drunk or intoxicated
Example
His frequent inebriety led to the loss of his job.
彼の頻繁な酩酊は仕事を失う原因となった。
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。
B1 adjective /ɪnˈfɔːrməl/

Informal

非公式; リラックス; カジュアル
Meaning
relaxed and friendly; not official or ceremonial; casual
Example
The meeting was informal and relaxed.
会議は非公式でリラックスしていました。
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。
C2 adjective /ɪnˈsuːpərəbl/

insuperable

克服できない
Meaning
Impossible to overcome or surpass.
Example
The team faced insuperable challenges during the expedition.
チームは遠征中に克服できない課題に直面しました。
B2 noun /ˌɪnstəˈbɪləti/

instability

不安定
Meaning
lack of stability or balance; tendency to change, fail, or collapse easily
Example
Political instability has slowed economic growth in the region.
政治的な不安定さが地域の経済成長を遅らせた。
C1 noun /ˈɪmɪdʒəri/

imagery

イメージ
Meaning
visually descriptive or figurative language, especially in a literary work
Example
The poet's use of imagery brought the scene to life.
詩人のイメージの使用は、シーンに命を吹き込みました。
C1 verb /ɪnˈsɪnjueɪt/

insinuate

Meaning
To suggest or hint something indirectly and often unpleasantly.
Example
He insinuated that she had lied about her qualifications.
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。
B1 noun /ˌɪntərˈækʃən/

interaction

相互作用
Meaning
The process of people or things acting upon or influencing each other.
Example
The teacher encouraged more interaction between students.
教師は生徒間のさらなるインタラクションを促進しました。
C1 noun ɪˌræʃ.ənˈæl.ɪ.ti

irrationality

非合理性, 非論理性, 不合理
Meaning
The quality of being illogical or unreasonable; lack of rational thought.
Example
His decision was driven by complete irrationality.
彼の決定は完全に非合理的でした。
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 adjective ˌɪn.ɪ.fɪˈkeɪ.ʃəs

inefficacious

効果がない
Meaning
Not producing any or the desired effect; ineffective.
Example
The treatment was inefficacious in curing the disease.
その治療法は病気の治癒に効果がありませんでした。
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 adjective /ˌɪmpɪˈkjuːniəs/

impecunious

貧乏
Meaning
Having little or no money; poor.
Example
He grew up in an impecunious family.
彼は貧乏な家族で育ちました。
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。
C1 verb /ɪnˈdʌkt/

induct

Meaning
to formally admit someone into a position, organization, or office
Example
She was inducted into the university's honor society.
C2 noun /ˌɪnkənˈɡruːəti/

incongruity

不一致
Meaning
The state of being inconsistent or out of place.
Example
The incongruity of his cheerful mood during the funeral shocked everyone.
葬式の最中に彼の陽気な気分の不一致は、皆を驚かせました。
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 noun /ˈɪnkjʊˌbeɪtər/

incubator

インキュベーター
Meaning
a device or environment that provides suitable conditions for eggs, cells, or infants to develop
Example
The premature baby was placed in an incubator for care.
未熟児はケアのためにインキュベーターに入れられました。
C2 noun (compound/erroneous entry) /ɪnˈɛksərəbl ɑːrmi/

inexorableinexorablearmy

止められない軍隊
Meaning
This appears to be a corrupted or concatenated form; interpreted as 'inexorable army' — an unstoppable or relentless force.
Example
The rebels feared the inexorable army approaching their stronghold.
反乱軍は自分たちの砦に近づいてくる止められない軍隊を恐れていた。
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。
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。
B1 abbreviation /ˌaɪˈiː/

ie

すなわち
Meaning
That is to say; used to clarify or explain something more precisely.
Example
Many amphibians, i.e., frogs and salamanders, can live both in water and on land.
多くの両生類、すなわちカエルとサラマンダーは、水中と陸上の両方で生きることができます。
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 /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 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。
C1 adjective /ɪnˈsɪdiəs/

insidious

陰険な
Meaning
Proceeding in a gradual, subtle way but with harmful effects.
Example
The insidious spread of misinformation can damage trust.
誤った情報の陰険な広がりは信頼を傷つける可能性がある。
C1 verb /ɪmˈploʊd/

implode

内爆
Meaning
To collapse or burst inward violently.
Example
The old building imploded during the demolition.
古い建物は解体中に内向きに崩壊しました。
B2 noun /ˌɪmɪˈɡreɪʃən/

immigration

移民
Meaning
the action of coming to live permanently in a foreign country
Example
Immigration policies vary from country to country.
移民政策は国によって異なります。
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。
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。
C2 noun /ˈɪɡ.nəˌmɪn.i/

ignominy

恥辱
Meaning
Public shame, disgrace, or dishonor.
Example
He lived the rest of his life in ignominy after the scandal.
スキャンダル後、彼は生涯を恥辱の中で過ごした。
C2 adjective /ˌɪn.ɪˈlʌk.tə.bəl/

ineluctable

Meaning
Impossible to avoid or escape; inevitable.
Example
Death is an ineluctable part of human existence.
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。
C1 adverb, adjective /ˌɪnkɑːɡˈniːtoʊ/

incognito

インコグニート
Meaning
In disguise or with one's identity concealed.
Example
The celebrity traveled incognito to avoid the paparazzi.
有名人はパパラッチを避けるためにインコグニートで旅行した。
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。
C2 adjective /ˌɪnkɒntrəˈvɜːtəbl/

incontrovertible

論争の余地がない
Meaning
impossible to deny or dispute; unquestionable
Example
The evidence was incontrovertible and proved his innocence.
その証拠は論争の余地がなく、彼の無罪を証明しました。
C1 adjective /ɪnˈstrʌktɪv/

instructive

教育的
Meaning
useful and informative; providing knowledge or instruction
Example
The lecture was highly instructive and engaging.
その講義は非常に教育的で魅力的でした。
B2 noun /ˈɪnˌteɪk/

intake

摂取
Meaning
the process of taking something in, especially food or drink
Example
He monitored his daily intake of calories to maintain a healthy diet.
彼は健康的な食事を維持するために毎日のカロリー摂取量を監視しました。
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。
B2 adverb /ɪnˈɛvɪtəbli/

inevitably

避けられない
Meaning
in a way that cannot be avoided or prevented
Example
Inevitably, the team faced challenges during the project.
避けられないことに、チームはプロジェクト中に挑戦に直面しました。
C1 adjective ɪˈneɪt

Innate

生まれつきのまたは自然の
Meaning
Existing from birth or natural
Example
She has an innate talent for music.
彼女は音楽において生まれつきの才能を持っている。
B2 noun ˌɪnɪˈkwɒlɪti

inequality

不平等
Meaning
Difference in size, degree, circumstances, etc.; lack of equality.
Example
The theme of inequality is prominent throughout the story.
不平等のテーマは物語全体にわたって顕著です。
A2 noun /ˌɪn.trəˈdʌk.ʃən/

introduction

紹介
Meaning
the action of introducing something or someone; an opening or beginning part
Example
The professor gave a brief introduction before starting the lecture.
教授は講義を始める前に簡単なイントロダクションをしました。
B2 verb /ɪmˈpoʊz/

impose

課す
Meaning
to force someone to accept something; to establish or apply by authority
Example
The government imposed new taxes on luxury goods.
政府は高級品に新しい税を課した。
B2 adjective /ˌɪn.trəˈdʌk.tər.i/

introductory

導入の
Meaning
Serving as an introduction; preliminary or preparatory.
Example
The professor gave an introductory lecture on economics.
教授は経済学についての導入の講義を行いました。
B1 verb ɪnˈspaɪər

inspire

インスパイアする
Meaning
To fill someone with the urge or ability to do or feel something, especially creative or noble.
Example
Artemis seeks to inspire future generations.
アルテミスは未来の世代にインスパイアを与えようとしています。
C2 adjective/noun /ɪnˈkɑːrnədiːn/

incarnadine

深紅
Meaning
a bright crimson or pinkish-red color
Example
The sky turned incarnadine at sunset.
太陽が沈むと空は深紅色に変わった。
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 adverb /ˈɪnwərdli/

inwardly

内面的に
Meaning
In the mind or spirit; not outwardly visible.
Example
She smiled outwardly but inwardly she was worried.
彼女は外見では微笑んだが、内心では心配していた。
C2 adjective /ˌɪɡ.nəˈmɪn.i.əs/

ignominious

不名誉な
Meaning
Marked by shame, disgrace, or humiliation.
Example
The team suffered an ignominious defeat in the finals.
チームは決勝で不名誉な敗北を喫した。
A1 adjective /ˈɪntrəstɪŋ/ or /ˈɪntəˌrɛstɪŋ/

interesting

面白い
Meaning
Arousing curiosity or attention; holding one’s interest.
Example
The documentary about space was very interesting.
宇宙についてのドキュメンタリーはとても面白かった。
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 /ˌɪndɪˈsaɪsɪv/

Indecisive

優柔不断な
Meaning
unable to make decisions quickly; hesitant; wavering
Example
She was indecisive about which university to attend.
彼女はどの大学に入学すべきか決めかねていた。
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 noun /ˌaɪ.diˈɒl.ə.dʒi/

ideology

イデオロギー
Meaning
A system of ideas and ideals, especially one that forms the basis of economic or political theory and policy.
Example
Democracy is based on the ideology of freedom and equality.
民主主義は自由と平等のイデオロギーに基づいています。
B2 adjective ˌɪnɪˈfɛktɪv

ineffective

効果がない
Meaning
Not producing any significant or desired effect; not achieving the intended result.
Example
Rote learning often proves to be ineffective.
暗記学習はしばしば効果がないことが証明されます。
B1 verb /ɪmˈprɛs/

impress

感動させる
Meaning
to cause someone to feel admiration or respect
Example
Her speech managed to impress the audience.
彼女のスピーチは聴衆を感動させました。
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。
C2 verb /ɪmˈpeɪl/

impale

突き刺す
Meaning
to pierce or fix something with a sharp object
Example
The knight was impaled by the enemy’s spear.
騎士は敵の槍で突き刺さった。
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。
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。
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。
A2 noun/verb /ˈaɪən/ or /ˈaɪərn/

iron

鉄 / アイロン
Meaning
a strong, hard metal used in construction; also to press clothes with heat
Example
He used an iron to smooth his shirt.
彼はシャツを滑らかにするためにアイロンを使った。
B1 adjective /ˌɪnɪkˈspɛnsɪv/

Inexpensive

安い; 手頃な; 経済的
Meaning
not costing a lot of money; affordable; budget-friendly
Example
This restaurant offers delicious and inexpensive meals for students.
このレストランは学生のためにおいしくて安い食事を提供しています。
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。
C2 adjective /ˌɪndɪˈvɜːrtɪbəl/

indivertible

Meaning
Not able to be turned aside or diverted.
Example
The judge's indivertible attention was on the case.
C1 adjective /ˌɪn.dɪˈspen.sə.bəl/

indispensable

不可欠
Meaning
Absolutely necessary, essential
Example
Water is indispensable for human survival.
水は人間の生存に不可欠です。
B1 verb /aɪˈdentɪfaɪ/

identify

識別する
Meaning
to recognize; to establish who someone is
Example
Can you identify the suspect?
容疑者を特定できますか？
B2 adjective /ɪmˈpɜːrfɪkt/

imperfect

不完全
Meaning
Not perfect; having faults or flaws.
Example
The painting was beautiful despite being imperfect.
その絵は美しかったが、完璧ではなかった。
C1 verb ɪˈnɪʃɪeɪtɪd

initiated

開始された
Meaning
Caused a process or action to begin; started something.
Example
The project was initiated to enhance marine biodiversity.
プロジェクトは海洋生物多様性を向上させるために開始されました。
C2 noun /ˈɪnˌɡreɪt/

ingrate

Meaning
An ungrateful person; someone who shows no appreciation.
Example
He worked hard for his friend, but the ingrate never thanked him.
B2 noun /ˈɪɡ.nər.əns/

Ignorance

無知
Meaning
lack of knowledge or information; the state of being uninformed about something
Example
His ignorance about basic computer skills made it difficult for him to find a job.
基本的なコンピュータースキルに関する彼の無知は、彼が仕事を見つけるのを難しくしました。
C2 verb /ˌɪntərˈsiːd/

intercede

Meaning
to act or plead on behalf of someone in difficulty or trouble; to intervene between parties to help resolve a dispute
Example
She interceded with the teacher to give her brother another chance.
C2 adjective /ɪnˈsɛnʃənt/

insentient

無感覚の
Meaning
Lacking perception, consciousness, or sensation.
Example
The rock is an insentient object with no awareness.
岩は意識のない無感覚の物体です。