addle-pate, ***, blockhead, bonehead, boob, cretin, dimwit, dingbat, dolt, dope, dork, dumbbell, dumbo, dummy, dunce, dunderhead, fool, goose, halfwit, idiot, ignoramus, imbecile, lamebrain, loony, loser, lunkhead, mental defective, muttonhead, nerd, numskull, ******, simp, simpleton, stoop, stupid, dodo, , dullard, dumb ***, dumb f'uck, dumb ****, dumb ox, dumbo, dumdum, dummy, dunce, moron, birdbrain, buffoon,donkey, drip, duffer, dullard, dumb bunny, dumb cluck, dumb head, dumb ox, dunderhead, fool, goof, goof ball, goon, half-baked, half-wit, idiot, ignoramus, imbecile, jackass, jerk, knucklehead, lame-brain, lightweight, loon, lout, lunkhead, moron, nerd, nincompoop, ninny, nitwit, numskull, oaf, pinhead, scatterbrain, schmuck, schnook, spaz, stoop, twit
take your pick