Answer:

somber

Answer	Crossword Clue
SOMBER	Like many minor-key compositions
SOMBER	Like the mood in a losing locker room
SOMBER	Like many works in minor keys

SOMBER	Dirgelike
SOMBER	Melancholy
SOMBER	Like a requiem
SOMBER	Serious
SOMBER	Not at all sunny
SOMBER	Unsmiling
SOMBER	Grave
SOMBER	Shadowy