heaviness vs uninterestingness

heaviness and uninterestingness both are nouns.

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

As nouns, uninterestingness is a hypernym of heaviness; that is, uninterestingness is a word with a broader meaning than heaviness:

heaviness: an oppressive quality that is laborious and solemn and lacks grace or fluency
uninterestingness: inability to capture or hold one's interest

heaviness (noun)	uninterestingness (noun)
the property of being comparatively great in weight	inability to capture or hold one's interest
used of a line or mark
unwelcome burdensome difficulty
an oppressive quality that is laborious and solemn and lacks grace or fluency
persisting sadness