Synonyms of 'duffer'

Arab, blockhead, boob, butterfingers, clumsy, dimwit, dolt, dope, dub, dumbbell, foul-up, goof, goofball, hawker, hick, higgler, huckster, idiot, ignoramus, incompetent, lummox, lump, monger, muff, numskull, oaf, ox, rube, slob, vendor