Entry 5 senses · 3 variants Webster, 1913 Duff /(dŭf)/ · IPA /dʌf/ n. n. v. t. 01 n. Dough or paste. 1. Dough or paste.[Prov. Eng.] 2. A stiff flour pudding, boiled in a bag; -- a term used especially by seamen; as, plum duff. 02 n. the buttocks; as, get off your duff and get to work. 1. the buttocks; as, get off your duff and get to work.[slang] Syn. rump; ass. 03 v. t. To treat or manipulate so as to give a specious appearance to; to fake; hence, to cheat. imp. & p. p. Duffed; p. pr. & vb. n. Duffing 1. To treat or manipulate so as to give a specious appearance to; to fake; hence, to cheat.[Colloq. or Slang] 2. In Australia, to alter the brands on (cattle, horses, etc.); to steal (cattle, etc.), and alter their brands.