body waste vs vomitus

body waste and vomitus both are nouns.

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

As nouns, vomitus is a hyponym of body waste; that is, vomitus 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
vomitus: the matter ejected in vomiting

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