非合理的

• Reading: ひごうりてき
• Romaji: higouriteki
• Kanji breakdown: 非 (hi) — non-, un-; 合 (gou) — fit; 理 (ri) — logic; 的 (teki) — -like
• Pronunciation: /hi.goː.ɾi.te.ki/

Meaning

Illogical; irrational; unreasonable. Describes something that defies sound reasoning.

A na-adjective formed by adding the negative prefix 非 to 合理的 (rational). Used to criticise decisions, behaviour, or systems that lack logical basis: 非合理的な考え (an irrational idea), 非合理的な慣習 (unreasonable customs). More academic than おかしい or 変 when discussing flawed reasoning.

Examples

1. 感情に流されて非合理的な決断をしてしまった。 I got swept up in emotions and made an irrational decision.
2. 非合理的なルールは見直すべきだ。 Irrational rules should be reconsidered.
3. 彼の行動は非合理的としか思えない。 His behavior can only be described as irrational.

Usage Guide

Context: academic, philosophy, debate

Tone: critical

Origin & History

Compound of 非 (hi, non-/un-) and 合理的 (gouriteki, rational). Together, 'not rational' — a formal negation used in analytical and critical discourse.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal