duff¹ / dəf/ • n. a flour pudding boiled or steamed in a cloth bag: a currant duff.duff² • n. 1. decaying vegetable matter covering the ground under trees.2. Mining coal dust; dross.• adj. Brit., inf. of very poor quality: duff lyrics. ∎  incorrect or false: she played a couple of duff notes.duff³ • v. [tr.] inf. 1. (duff someone up) Brit. beat someone up.2. Golf Brit. mishit (a shot).duff⁴ • n. inf. a person's buttocks: I did not get where I am today by sitting on my duff.

duff (dial.) dough; flour-pudding boiled in a bag. XIX. north. var. of DOUGH.