vomit up vs barf

vomit up is not a noun while barf is a noun.

Word	Noun	Adjective	Verb	Adverb
vomit up	No	No	Yes	No
barf	Yes	No	Yes	No

As verbs, vomit up and barf are synonyms defined as:

Other synonyms of vomit up include be sick, cast, cat, chuck, disgorge, honk, puke, purge, regorge, regurgitate, retch, sick, spew, spue, throw up, upchuck, vomit.

vomit up (noun)	barf (noun)
	the matter ejected in vomiting

vomit up (verb)	barf (verb)
eject the contents of the stomach through the mouth	eject the contents of the stomach through the mouth