Synonyms for Gloominess (same or very similar meaning)
WordNet sense 1 (an atmosphere of depression and melancholy):
gloom, glumness
WordNet sense 2 (a feeling of melancholy apprehension):
somberness, sombreness
WordNet sense 3 (the quality of excessive mournfulness and uncheerfulness):
lugubriousness, sadness
From the ODE community, based on WordNet
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