clod

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

bead, drop, globule

block, body, bulk

particle, piece, portion

bit, chip, crumb, granule, morsel, nubbin, patch, scrap

blackland, clay, gault [chiefly British], gley, guck (or gook), gumbo, kaolin, muck, mud

dust, gravel, sand

humus, loam, topsoil

alluvium, colluvium, detritus, loess, marl, sediment, shingle, silt

duff, mull

subsoil, substratum