broadness vs heaviness

broadness and heaviness both are nouns.

Word	Noun	Adjective	Verb	Adverb
broadness	Yes	No	No	No
heaviness	Yes	No	No	No

As nouns, heaviness is a hyponym of broadness; that is, heaviness is a word with a more specific, narrower meaning than broadness:

Other hyponyms of broadness include thickness.

broadness (noun)	heaviness (noun)
the property of being wide; having great width	the property of being comparatively great in weight
	used of a line or mark
	unwelcome burdensome difficulty
	an oppressive quality that is laborious and solemn and lacks grace or fluency
	persisting sadness