butcher vs knacker

butcher and knacker both are nouns.

Word	Noun	Adjective	Verb	Adverb
butcher	Yes	No	Yes	No
knacker	Yes	No	No	No

As nouns, knacker is a hyponym of butcher; that is, knacker is a word with a more specific, narrower meaning than butcher:

butcher (noun)	knacker (noun)
a person who slaughters or dresses meat for market	someone who buys up old horses for slaughter
a brutal indiscriminate murderer	someone who buys old buildings or ships and breaks them up to recover the materials in them
a retailer of meat
someone who makes mistakes because of incompetence

butcher (verb)	knacker (verb)
kill (animals) usually for food consumption