grandness vs brilliance

grandness and brilliance both are nouns.

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

As nouns, grandness and brilliance are synonyms defined as:

grandness and brilliance: the quality of being magnificent or splendid or grand

Other synonyms of grandness include grandeur, magnificence, splendor, splendour.

grandness (noun)	brilliance (noun)
the quality of being magnificent or splendid or grand	a light within the field of vision that is brighter than the brightness to which the eyes are adapted
unusual largeness in size or extent or number	the quality of being magnificent or splendid or grand
splendid or imposing in size or appearance	unusual mental ability
a prominent status