expression, na-adjective, noun
Describes a person who acts like they know everything, often in a cheeky or impertinent way. Used as a noun or adjectival noun (e.g., 利いた風な口をきく).
He always says know-it-all things.
Don't talk so cheekily.
Standard kanji spelling; 利いた means 'effective' or 'clever', and 風 means 'air' or 'manner'.
Alternate spelling using 聞いた 'heard', implying a know-it-all attitude from hearsay.
Kana spelling, common in casual writing.
From 利いた (past form of 利く 'to be effective, clever') + 風 'manner, air'. The alternate spelling 聞いた風 uses 聞く 'to hear', suggesting a know-it-all attitude based on hearsay. The exact origin is uncertain, but it likely emerged as a set phrase describing someone who acts clever or well-informed.