n. 1 failure, Colloq flop, lead balloon, lemon, washout, Colloq US and Canadian dog, clinker Her second novel certainly proved a dud - it sold only ten copies
adj. 2 worthless, valueless, broken, unusable, useless, inoperative, non-functioning, inoperative, malfunctioning, Colloq kaput, bust(ed), Brit duff They deliberately supplied us with dud ammunition