tenesmus vs spasm

tenesmus and spasm both are nouns.

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

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

tenesmus: painful spasm of the anal sphincter along with an urgent desire to defecate without the significant production of feces; associated with irritable bowel syndrome
spasm: a painful and involuntary muscular contraction

Other hypernyms of tenesmus include cramp, muscle spasm.

tenesmus (noun)	spasm (noun)
painful spasm of the anal sphincter along with an urgent desire to defecate without the significant production of feces; associated with irritable bowel syndrome	(pathology) sudden constriction of a hollow organ (as a blood vessel)
	a painful and involuntary muscular contraction