gloominess vs sadness

gloominess and sadness both are nouns.

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

As nouns, gloominess and sadness are synonyms defined as:

gloominess and sadness: the quality of excessive mournfulness and uncheerfulness

Other synonyms of gloominess include lugubriousness.

gloominess (noun)	sadness (noun)
the quality of excessive mournfulness and uncheerfulness	the quality of excessive mournfulness and uncheerfulness
The property of having a frowning or scowling appearance.	emotions experienced when not in a state of well-being
a feeling of melancholy apprehension	the state of being sad
an atmosphere of depression and melancholy