The term 'dark and gloomy' can be described by the crossword solutions of MURKY (5 letters), DUN (3 letters), somber (6 letters), DISMAL (6 letters), DREAR (5 letters), and STYGIAN (7 letters). MURKY is an adjective that means dark, opaque, and thick. DUN is an adjective that means a dull greyish-brown color. Somber is an adjective that means dark or gloomy in character or atmosphere. DISMAL is an adjective that means causing a feeling of gloom or depression. DREAR is an adjective that means dull, DISMAL, and depressing. STYGIAN is an adjective that means dark and gloomy, like the river Styx in Greek mythology.