largeness vs fullness

largeness and fullness both are nouns.

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

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

largeness (noun)	fullness (noun)
the property of having a relatively great size	greatness of volume
large or extensive in breadth or importance or comprehensiveness	the property of a sensation that is rich and pleasing
the quality of being pretentious (behaving or speaking in such a manner as to create a false appearance of great importance or worth)	the condition of being filled to capacity
the capacity to understand a broad range of topics	completeness over a broad scope