struggle vs exertion

struggle and exertion both are nouns.

Word	Noun	Adjective	Verb	Adverb
struggle	Yes	No	Yes	No
exertion	Yes	No	No	No

As nouns, exertion is a hypernym of struggle; that is, exertion is a word with a broader meaning than struggle:

Other hypernyms of struggle include effort, elbow grease, sweat, travail.

struggle (noun)	exertion (noun)
strenuous effort	use of physical or mental energy; hard work
an energetic attempt to achieve something
an open clash between two opposing groups (or individuals)

struggle (verb)	exertion (verb)
be engaged in a fight; carry on a fight
to exert strenuous effort against opposition
climb awkwardly, as if by scrambling
make a strenuous or labored effort