Synonyms and related words :
abnormal, absurd, aliene, ass, balmy, batty, bedlamite, bereft of reason, borderline case, born fool, brainsick, buffoon, clown, crackbrain, crackbrained, cracked, crackpot, crank, crazed, crazy, cuckoo, daft, deluded, dement, demented, demoniac, deprived of reason, deranged, ding-a-ling, disoriented, distraught, doodle, egregious ass, energumen, fanatic, fantastic, figure of fun, flake, flighty, fool, fou, hallucinated, harebrain, idiot, ignoramus, insane, irrational, jackass, kook, loco, loon, loony, mad, maddened, madman, maniac, manic, mazed, mental, mentally deficient, meshuggah, meshuggenah, milksop, moon-struck, mooncalf, neuropath, neurotic, non compos, non compos mentis, noncompos, not all there, not right, nut, odd, of unsound mind, off, paranoid, perfect fool, phrenetic, potty, preposterous, psycho, psychoneurotic, queer, raver, raving lunatic, reasonless, schmuck, screwball, senseless, sick, softhead, sop, stark-mad, stark-staring mad, strange, stupid ass, tetched, tomfool, touched, unbalanced, unhinged, unsane, unsettled, unsound, wacky, wandering, weirdo, witless, zany