ponderosity vs massiveness

ponderosity and massiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
ponderosity	Yes	No	No	No
massiveness	Yes	No	No	No

As nouns, ponderosity and massiveness are synonyms defined as:

Other synonyms of ponderosity include heft, heftiness, ponderousness.

ponderosity (noun)	massiveness (noun)
the property of being large in mass	an unwieldy largeness
	the property of being large in mass