largeness vs grandness

largeness and grandness both are nouns.

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

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

largeness (noun)	grandness (noun)
the property of having a relatively great size	the quality of being magnificent or splendid or grand
large or extensive in breadth or importance or comprehensiveness	unusual largeness in size or extent or number
the quality of being pretentious (behaving or speaking in such a manner as to create a false appearance of great importance or worth)	splendid or imposing in size or appearance
the capacity to understand a broad range of topics	a prominent status