stuffiness vs sombreness

stuffiness and sombreness both are nouns.

Word	Noun	Adjective	Verb	Adverb
stuffiness	Yes	No	No	No
sombreness	Yes	No	No	No

As nouns, sombreness is a hypernym of stuffiness; that is, sombreness is a word with a broader meaning than stuffiness:

Other hypernyms of stuffiness include graveness, gravity, soberness, sobriety, somberness.

stuffiness (noun)	sombreness (noun)
dull and pompous gravity	a manner that is serious and solemn
the quality of being close and poorly ventilated	a feeling of melancholy apprehension
state of obstruction or stoppage or air in the nose or throat	a state of partial or total darkness