clodhopper

boor, clod, clown, gawk, lout, oaf

greenhorn, tenderfoot

peasant, peon

backwoodsman, mountaineer

chump, loser, schlemiel (also shlemiel), turkey

slouch

airhead, birdbrain, blockhead, blunderer, bonehead, bubblehead, chowderhead, chucklehead, clodpoll (or clodpole), clot [British], cluck, clunk, cuddy (or cuddie) [British dialect], deadhead, dim bulb [slang], dimwit, dip, dodo, dolt, donkey, doofus [slang], dope, dork [slang], dullard, dumbbell, dumbhead, dum-dum, dummkopf, dummy, dunce, dunderhead, fathead, galoot [slang], gander, golem, 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), pinhead, prat [British], ratbag [chiefly Australian], saphead, schlub (also shlub) [slang], schnook [slang], simp, simpleton, stock, stupe, stupid, thickhead, turkey, woodenhead, yahoo, yo-yo

anthropoid, ape, beast, boor, brute, cad, churl, clown, creep, cretin, cur, heel, louse, skunk, snake, stinker, tyke (also tike) [chiefly British], villain

booby, fool, goose, loony (also looney), lunatic, madman, nut

featherbrain, scatterbrain

rascal, rogue, scamp