airhead, birdbrain, blockhead, bonehead, bubblehead, chowderhead, chucklehead, clodpoll(or clodpole), clot(British), cluck, clunk, cretin, cuddy(or cuddie, British dialect), deadhead, dim bulb(slang), dimwit, dip, dodo, dolt, donkey, doofus(slang), dope, dork(slang), dullard, dum-dum, dumbbell, dumbhead, dummkopf, dummy, dunce, dunderhead, fathead, gander, goof, goon, half-wit, hammerhead, hardhead, idiot, ignoramus, imbecile, jackass, know-nothing, knucklehead, lamebrain, loggerhead(chiefly dialect), loon, lump, lunkhead, meathead, mome(archaic), moron, mug(chiefly British), mutt, natural, nimrod(slang), nincompoop, ninny, ninnyhammer, nit(chiefly British), nitwit, noddy, noodle, numskull(or numbskull), oaf, pinhead, prat(British), ratbag(chiefly Australian), saphead, schlub(also shlub, slang), schnook(slang), simpleton, stock, stupe, stupid, thickhead, turkey, woodenhead, yahoo, yo-yo

booby, buffoon, fool, goose, loony, lunatic, madman, nut, zanylosergawkfeatherbrain, scatterbrainbeast, boor, cad, churl, clown, creep, cur, heel, jerk, skunk, snake, stinker, villain

dumb cluck