knockout punch vs biff

knockout punch and biff both are nouns.

Word	Noun	Adjective	Verb	Adverb
knockout punch	Yes	No	No	No
biff	Yes	No	Yes	No

As nouns, biff is a hypernym of knockout punch; that is, biff is a word with a broader meaning than knockout punch:

knockout punch: a hard punch that renders the opponent unable to continue boxing
biff: (boxing) a blow with the fist

Other hypernyms of knockout punch include clout, lick, poke, punch, slug.

knockout punch (noun)	biff (noun)
a hard punch that renders the opponent unable to continue boxing	(boxing) a blow with the fist

knockout punch (verb)	biff (verb)
	strike, usually with the fist