vastness vs enormousness

vastness and enormousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
vastness	Yes	No	No	No
enormousness	Yes	No	No	No

As nouns, vastness and enormousness are synonyms defined as:

vastness and enormousness: unusual largeness in size or extent or number

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

vastness (noun)	enormousness (noun)
unusual largeness in size or extent or number	unusual largeness in size or extent or number