somberness vs gloominess

somberness and gloominess both are nouns.

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

As nouns, somberness and gloominess are synonyms defined as:

Other synonyms of somberness include gloom, sombreness.

somberness (noun)	gloominess (noun)
a manner that is serious and solemn	the quality of excessive mournfulness and uncheerfulness
a feeling of melancholy apprehension	The property of having a frowning or scowling appearance.
a state of partial or total darkness	a feeling of melancholy apprehension
	an atmosphere of depression and melancholy