adj. bad, useless, worthless, unworkable, inoperable, inoperative, broken; fake, false, counterfeit, Colloq dud, phoney or US also phony We couldn't get that duff radio to work We were provided with duff papers for crossing the border.
DUFF
Meaning of DUFF in English
Oxford thesaurus English vocab. Английский словарь Оксфорд тезаурус. 2012