[n] these words are used to express a low opinion of someone's intelligence
blockhead, bonehead, dunce, fuckhead, hammerhead, knucklehead, loggerhead, lunkhead, muttonhead, numskull, shithead
addlebrain, addlehead, addlepate, beefhead, blockhead, blubberhead, blunderhead, bonehead, bufflehead, cabbagehead, chowderhead, chucklehead, clodhead, clodpate, clodpoll, dolthead, dope, dullhead, dumbhead, dunderpate, fathead, jolterhead, jughead, knuck