knacker

Etymology

From Old Norse hnak (“saddle”) (whence Icelandic hnakkur (“saddle”)), hur (“horse”) — the profession of saddlemaker.

noun

1. One who makes knickknacks, toys, etc.
2. One of two or more pieces of bone or wood held loosely between the fingers, and struck together by moving the hand; a clapper.
   A Bachanalian dancing the Spanish Morisco, with knackers at his fingers. 1649, William Cavendish, 1st Duke of Newcastle, The Variety
3. A harness maker.
4. One who slaughters and (especially) renders worn-out livestock (especially horses) and sells their flesh, bones and hides.
5. One who dismantles old ships, houses, etc. and sells their components.
6. (Ireland, Britain, offensive) A member of the Travelling Community; a Gypsy.
7. (Ireland, offensive, slang) A person of lower social class; a chav, skanger or scobe.
8. (UK, slang, chiefly in the plural) A testicle.
   He looked like someone had put a 9mm full metal jacket round through his left scrotum. He even had his mouth open in some parody of a soundless scream, much as I imagined I would do if someone shot my left knacker off. 2013, Perry Gamsby, Never Be Unsaid, page 136
9. An old, worn-out horse.
   Believe me, you can get an old knacker for cheap at the glue yard, but it won't carry you as far as a thoroughbred! 2014, K. Bannerman, Mark of the Magpie, page 170
10. (UK, dialect, obsolete) A collier's horse.

verb

1. (UK, slang, transitive) To tire out, exhaust.
   Carrying that giant statue up those stairs completely knackered me.
2. (UK, slang, transitive) To reprimand.