gloominess vs facial expression

gloominess and facial expression both are nouns.

Word	Noun	Adjective	Verb	Adverb
gloominess	Yes	No	No	No
facial expression	Yes	No	No	No

As nouns, facial expression is a hypernym of gloominess; that is, facial expression is a word with a broader meaning than gloominess:

Other hypernyms of gloominess include aspect, expression, face, look.

gloominess (noun)	facial expression (noun)
the quality of excessive mournfulness and uncheerfulness	the feelings expressed on a person's face
The property of having a frowning or scowling appearance.	a gesture executed with the facial muscles
a feeling of melancholy apprehension
an atmosphere of depression and melancholy