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.
I oppose irrational decisions.
非合理 is a slightly more technical or philosophical way to say 'irrational', whereas 不合理 is the everyday word for the same idea.
illogical; irrational
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.