insane

adjective

1. afflicted with or characteristic of mental derangement

- was declared insane

- insane laughter

Similar word(s): irrational, unreasonable, balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kookie, kooky, loony, loopy, nuts, nutty, wacky, whacky, brainsick, crazy, demented, disturbed, mad, sick, unbalanced, unhinged, certifiable, certified, crackbrained, idiotic, crazed, deranged, fey, touched, hebephrenic, lunatic, moonstruck, maniac, maniacal, maniclike, unsound, unstable, paranoid, psychopathic, psychopathologic, psychopathological, psychotic, wild, schizophrenic, screwy

2. very foolish

- took insane risks behind the wheel

Similar word(s): foolish, harebrained, mad