heftiness vs muscle

heftiness and muscle both are nouns.

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

As nouns, heftiness and muscle are synonyms defined as:

Other synonyms of heftiness include brawn, brawniness, muscularity, sinew.

heftiness (noun)	muscle (noun)
possessing muscular strength	possessing muscular strength
the property of being large in mass	authority or power or force (especially when used in a coercive way)
	one of the contractile organs of the body
	animal tissue consisting predominantly of contractile cells
	a bully employed as a thug or bodyguard

heftiness (verb)	muscle (verb)
	make one's way by force