不合理|ふごうりfugouri[2]nakadaka (mid-high)

1. na-adjective, nounirrational; illogical; unreasonable; absurd; inconsistent
   間違まちがいを一度いちども認みとめないというのは不合理ふごうりである。↗

   It's absurd never to admit your mistakes.

• Synonym理不尽りふじんNeutralUnreasonableness forced on you by others — high-handed, unfair demands; carries indignation. 「不合理」 centers on illogic, especially in systems and practices.
• Synonym不条理ふじょうりWrittenWritten word for what defies reason — the absurd, as in 「不条理劇」; also real-world unfairness like 「不条理な扱い」. Leans toward written use.
• Synonym非合理ひごうりWrittenWritten, often philosophical: lacking rationality, defying logical explanation; also used in criticism, as in 「非合理な判断」.
• Synonym無茶むちゃCasualColloquial: reckless, going to excess, as in 「無茶をする」; it can also mean unreasonable, but the focus is on overdoing it rather than on flawed logic.
• SynonymめちゃくちゃCasualColloquial: absurd and chaotic; near-synonymous with 「無茶苦茶」 in sense and force.
• Synonym非論理的ひろんりてきNeutralIllogical in the strict sense: reasoning that doesn't hold up, as in 「非論理的な主張」. Neutral register.
• Synonym不道理ふどうりWrittenWritten term for what defies reason, but rare even in prose; say 「不合理」 in most cases.
• Related非常識ひじょうしきNeutralLacking common sense: conduct that flouts accepted norms, as in 「非常識な人」. Judges a person's behavior, not a system's logic.
• Related荒唐無稽こうとうむけいWrittenWritten four-character idiom: preposterous nonsense; stresses having no basis in fact at all.
• RelatedむちゃくちゃCasualColloquial and strong in tone: chaotic, all mixed up, unreasonable. Much more casual than 不合理.
• Related矛盾むじゅんNeutralContradiction — statements or facts that don't add up, as in 「矛盾した発言」. Points to internal inconsistency, not general unreasonableness.
• RelatedばかばかしいCasualColloquial: so absurd it is laughable; carries contempt or scorn.
• Related背理はいりWrittenWritten, logic-oriented: going against reason, as in 「背理法」 (proof by contradiction); scholarly, not everyday.
• Related阿呆らしいあほらしいCasualColloquial, chiefly Kansai: laughably absurd; expresses disdain, as in 「あほらしい話」.
• Antonym合理ごうりNeutralThe direct antonym: rational and logical. 「不合理」 simply negates it.

Use 「不合理」 for systems or practices that are illogical or unreasonable, as in 「不合理な規則」 and 「不合理な差別」. When the other party is overbearing and unreasonable, say 「理不尽」; for philosophical absurdity, 「不条理」; for self-contradiction, 「矛盾」; for something laughably absurd in speech, 「馬鹿馬鹿しい」. The opposite is 「合理」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 道理どうりに合あわないこと。
2. 道理どうりに合あわないさま。