Synonyms and related words :
Boeotian, block, clod, cluck, dimwit, dolt, donkey, dope, dullard, dumb cluck, dumbbell, dummy, dunce, featherweight, gowk, jobbernowl, lackwit, lamebrain, lightweight, looby, loon, niais, nincompoop, ninny, ninnyhammer, noddy, pinhead, put, simp, stupid, thickwit, witling