duff

noun11

1. •
   (US, slang) The buttocks.
2. •
   A stiff flour pudding, often with dried fruit, boiled in a cloth bag, or steamed.

   • The storekeeper had sent them an unbroken case of canned plum pudding, and probably by this time he was wondering what had become of that blanky case of duff. — 1901
3. •
   A pudding-style dessert, especially one made with plums or (in the Bahamas) guavas.
4. •
   Something spurious or fake; a counterfeit; a worthless thing; a defective thing.
5. •
   (US, Scotland) Decaying vegetable matter on the forest floor.

   • The moisture content of the deep pockets of rotten wood was much greater than of the litter-derived duff layer. — 1991
6. •
   Coal dust, especially that left after screening or combined with other small, unsaleable bits of coal.
7. •
   Fine and dry coal in small pieces, usually anthracite.

   • The great bulk of the coal burnt under our boilers is duff of a very small size, and a mixed coal of duff, peas, and small nuts. — 1917
8. •
   (UK) A mixture of coal and rock.
9. •
   (slang) An error.
10. •
    (dialect) Dough.
11. •
    (slang) The bits left in the bottom of the bag after the booty has been consumed, like crumbs.

verb4

1. •
   To hit the ground behind the ball.
2. •
   (Australia) To alter the branding of stolen cattle; to steal cattle.
3. •
   (slang, no longer used) To disguise something to make it look new.
4. •
   (slang, no longer used) To sell spurious goods, often under pretence of their being stolen or smuggled.

adjective1

1. •
   (UK) Worthless; not working properly, defective.

   • Why do I always get a shopping trolley with duff wheels?

noun1

1. •
   (slang, offensive) Acronym of dumb/designated ugly fat friend, an attractive woman's less attractive friend.