gloom

(noun) a state of partial or total darkness. Synonyms: somberness, sombreness. Example: "He struck a match to dispel the gloom."

(noun) a feeling of melancholy apprehension. Synonyms: gloominess, somberness, sombreness.

(noun) an atmosphere of depression and melancholy. Synonyms: gloominess, glumness. Example: "Gloom pervaded the office."