gloominess vs somberness

gloominess and somberness both are nouns.

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

As nouns, gloominess and somberness are synonyms defined as:

Other synonyms of gloominess include gloom, sombreness.

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