largeness vs giantism

largeness and giantism both are nouns.

Word	Noun	Adjective	Verb	Adverb
largeness	Yes	No	No	No
giantism	Yes	No	No	No

As nouns, giantism is a hyponym of largeness; that is, giantism is a word with a more specific, narrower meaning than largeness:

largeness (noun)	giantism (noun)
the property of having a relatively great size	excessive largeness of stature
large or extensive in breadth or importance or comprehensiveness	excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland
the quality of being pretentious (behaving or speaking in such a manner as to create a false appearance of great importance or worth)
the capacity to understand a broad range of topics