expulsion vs vomit

expulsion and vomit both are nouns.

Word	Noun	Adjective	Verb	Adverb
expulsion	Yes	No	No	No
vomit	Yes	No	Yes	No

As nouns, vomit is a hyponym of expulsion; that is, vomit is a word with a more specific, narrower meaning than expulsion:

expulsion: the act of expelling or projecting or ejecting
vomit: the reflex act of ejecting the contents of the stomach through the mouth

expulsion (noun)	vomit (noun)
the act of expelling or projecting or ejecting	the reflex act of ejecting the contents of the stomach through the mouth
the act of forcing out someone or something	a medicine that induces nausea and vomiting
squeezing out by applying pressure	the matter ejected in vomiting

expulsion (verb)	vomit (verb)
	eject the contents of the stomach through the mouth