Downbeat, glum (6)
I believe the answer is:
morose
I believe this clue is a double definition.
'downbeat' is the first definition.
(I've seen this in another clue)
'glum' is the second definition.
(I know that glum can be written as morose)
(Other definitions for morose that I've seen before include "Peevish and gloomy" , "Miserable" , "Sad" , "Sullen and gloomy" , "Melancholy" .)