vomit up vs retch

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

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

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

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

vomit up (noun)	retch (noun)
	an involuntary spasm of ineffectual vomiting

vomit up (verb)	retch (verb)
eject the contents of the stomach through the mouth	eject the contents of the stomach through the mouth
	make an unsuccessful effort to vomit; strain to vomit