- a person who buys animal carcasses or slaughters useless livestock for a knackery or rendering works.
- a person who buys and dismembers old houses, ships, etc., to salvage usable parts, selling the rest as scrap.
- Dialect. an old, sick, or useless farm animal, especially a horse.
- Obsolete. a harness maker; a saddler.
- a person who buys up old horses for slaughter
- a person who buys up old buildings and breaks them up for scrap
- (usually plural) slang another word for testicle
- Irish slang a despicable person
- (tr; usually passive) slang to exhaust; tire
usually in past tense, knackered, “to kill, castrate” (1855), but most often used in weakened sense of “to tire out” (1883); apparently from knacker (n.) “worn-out or useless horse,” 1812, of unknown origin; possibly from a dialectal survival of a Scandinavian word represented by Old Norse hnakkur “saddle,” hnakki “back of the neck,” and thus possibly related to neck (n.).