Melancholy

mel·an·chol·y/ˈmelənˌkälē/ 

Noun:A deep, pensive, and long-lasting sadness.Adjective:Sad, gloomy, or depressed.Synonyms:

noun.  sadness - melancholia - gloom - sorrow - dejection
adjective.  sad - gloomy - melancholic - mournful - dismal - blue