vomit vs keep down

vomit is a noun but keep down is not a noun.

Word	Noun	Adjective	Verb	Adverb
vomit	Yes	No	Yes	No
keep down	No	No	Yes	No

vomit (noun)	keep down (noun)
the reflex act of ejecting the contents of the stomach through the mouth
a medicine that induces nausea and vomiting
the matter ejected in vomiting

vomit (verb)	keep down (verb)
eject the contents of the stomach through the mouth	manage not to throw up
	place a limit on the number of
	put down by force or intimidation