ponderosity vs heftiness

ponderosity and heftiness both are nouns.

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

As nouns, ponderosity and heftiness are synonyms defined as:

Other synonyms of ponderosity include heft, massiveness, ponderousness.

ponderosity (noun)	heftiness (noun)
the property of being large in mass	possessing muscular strength
	the property of being large in mass