duffer

n (dated infml 旧, 口) stupid or incompetent person 笨蛋; 无能的人: I was always a bit of a duffer at maths. 我在数学方面总是有点笨.

duck-yard, ducking, duckling, ducks and drakes, duckweed, duct, ductile, ductility, ductless gland, dud, dude, dudgeon, duds, due, due to, duel, duellist, duenna, duet, duff, duffle (also duffel), duffle bag, duffle-coat, dug, dug-out, duke, dukedom, dulcet, dulcimer, dull, dullard, dullness, dully, duly, dumb, dumb show, dumb waiter, dumb-bell, dumbfound (also dumfound), dumbly,