na-adjective, noun
illogicality; irrationality
Refers to the quality of being illogical or not based on reason. Often used in philosophical or critical contexts.
彼の主張は非合理だ。
His argument is illogical.
非合理な決定に反対する。
I oppose irrational decisions.
Compound of 非 (hi, 'non-') and 合理 (gōri, 'rationality'). The exact historical derivation is uncertain, but the word follows a standard Sino-Japanese pattern for forming abstract nouns.