1) Blue 2) Melancholiac 3) Melancholy 4) Morose 5) Mournful 6) Sad 1) Melancholy 
• (n.) One affected with a gloomy state of mind. • (a.) Given to melancholy; depressed; melancholy; dejected; unhappy. • (n.) A gloomy state of mind; melancholy.
1. Relating to or characteristic of melancholia. ... 2. Formerly, denoting a temperament characterised by irritability and a pessimistic outlook. ... 3. A person who is exhibiting melancholia. ... (05 Mar 2000) ... 
Mel'an·chol`ic adjective [ Latin melancholicus , Greek ...: confer French mélancholique .] Given to melancholy; depressed; melancholy; dejected; unhappy. « Just as the melancholic eye Sees fleets and armies in the sky.» Prior. 
Type: Term Pronunciation: mel′ăn-kol′ik Definitions: 1. Relating to or characteristic of melancholia. 2. Formerly, denoting a temperament characterized by irritability and a pessimistic outlook. 3. A person who exhibits melancholia.
[n] - someone subject to melancholia
melancholiac noun someone subject to melancholia