large person vs giant

large person and giant both are nouns.

Word	Noun	Adjective	Verb	Adverb
large person	Yes	No	No	No
giant	Yes	Yes	No	No

As nouns, giant is a hyponym of large person; that is, giant is a word with a more specific, narrower meaning than large person:

Other hyponyms of large person include butterball, fat person, fatso, fatty, roly-poly, heavyweight, hulk, whale.

large person (noun)	giant (noun)
a person of greater than average size	any creature of exceptional size
	an unusually large enterprise
	a very bright star of large diameter and low density (relative to the Sun)
	someone that is abnormally large and powerful
	a person of exceptional importance and reputation
	an imaginary figure of superhuman size and strength; appears in folklore and fairy tales
	a very large person; impressive in size or qualities

large person (adjective)	giant (adjective)
	of great mass; huge and bulky