stodginess vs somberness

stodginess and somberness both are nouns.

Word	Noun	Adjective	Verb	Adverb
stodginess	Yes	No	No	No
somberness	Yes	No	No	No

As nouns, somberness is a hypernym of stodginess; that is, somberness is a word with a broader meaning than stodginess:

Other hypernyms of stodginess include graveness, gravity, soberness, sobriety, sombreness.

stodginess (noun)	somberness (noun)
dull and pompous gravity	a manner that is serious and solemn
	a feeling of melancholy apprehension
	a state of partial or total darkness