hand-to-hand struggle vs grappling

hand-to-hand struggle and grappling both are nouns.

Word	Noun	Adjective	Verb	Adverb
hand-to-hand struggle	Yes	No	No	No
grappling	Yes	No	No	No

As nouns, hand-to-hand struggle and grappling are synonyms defined as:

hand-to-hand struggle and grappling: the act of engaging in close hand-to-hand combat

Other synonyms of hand-to-hand struggle include grapple, wrestle, wrestling.

hand-to-hand struggle (noun)	grappling (noun)
the act of engaging in close hand-to-hand combat	the act of engaging in close hand-to-hand combat
	the sport of hand-to-hand struggle between unarmed contestants who try to throw each other down