body waste vs barf

body waste and barf both are nouns.

Word	Noun	Adjective	Verb	Adverb
body waste	Yes	No	No	No
barf	Yes	No	Yes	No

As nouns, barf is a hyponym of body waste; that is, barf is a word with a more specific, narrower meaning than body waste:

body waste: waste matter (as urine or sweat but especially feces) discharged from the body
barf: the matter ejected in vomiting

body waste (noun)	barf (noun)
waste matter (as urine or sweat but especially feces) discharged from the body	the matter ejected in vomiting

body waste (verb)	barf (verb)
	eject the contents of the stomach through the mouth