immensity vs sizeableness

immensity and sizeableness both are nouns.

Word	Noun	Adjective	Verb	Adverb
immensity	Yes	No	No	No
sizeableness	Yes	No	No	No

As nouns, immensity and sizeableness are synonyms defined as:

immensity and sizeableness: unusual largeness in size or extent or number

Other synonyms of immensity include enormousness, grandness, greatness, immenseness, vastness, wideness.

immensity (noun)	sizeableness (noun)
unusual largeness in size or extent or number	unusual largeness in size or extent or number