INSANE Meaning of INSANE in English adj. 1 not of sound mind; mad. 2 colloq. extremely foolish; irrational. insanely adv. insaneness n. insanity n. (pl. -ies). [ L insanus (as IN-(1), sanus healthy) ] Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012