grappling vs struggle

grappling and struggle both are nouns.

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

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

grappling (noun)	struggle (noun)
the act of engaging in close hand-to-hand combat	strenuous effort
the sport of hand-to-hand struggle between unarmed contestants who try to throw each other down	an energetic attempt to achieve something
	an open clash between two opposing groups (or individuals)

grappling (verb)	struggle (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