retch vs spasm

retch and spasm both are nouns.

Word	Noun	Adjective	Verb	Adverb
retch	Yes	No	Yes	No
spasm	Yes	No	No	No

As nouns, spasm is a hypernym of retch; that is, spasm is a word with a broader meaning than retch:

retch: an involuntary spasm of ineffectual vomiting
spasm: (pathology) sudden constriction of a hollow organ (as a blood vessel)

retch (noun)	spasm (noun)
an involuntary spasm of ineffectual vomiting	(pathology) sudden constriction of a hollow organ (as a blood vessel)
	a painful and involuntary muscular contraction

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