[duff] n [E dial., alter. of dough] (1816) 1: a boiled or steamed pudding often containing dried fruit
2: the partly decayed organic matter on the forest floor
3: fine coal: slack
[2]duff n [origin unknown] (ca. 1888): buttocks "get off your ~" [3]duff adj [duff, n., something worthless, fr. [1]duff] (ca. 1889) Brit: inferior, worthless