melancholy

(noun) a feeling of thoughtful sadness.

(noun) a constitutional tendency to be gloomy and depressed.

(noun) a humor that was once believed to be secreted by the kidneys or spleen and to cause sadness and melancholy. Synonyms: black bile.

(adj) characterized by or causing or expressing sadness. Synonyms: melancholic. Examples: "Growing more melancholy every hour." "Her melancholic smile." "We acquainted him with the melancholy truth."

(adj) grave or even gloomy in character. Synonyms: somber, sombre. Examples: "Solemn and mournful music." "A suit of somber black." "A somber mood."