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