Sulky, morose (6)
I believe the answer is:
sullen
I believe this clue is a double definition.
'sulky' is the first definition.
(I've seen this in another clue)
'morose' is the second definition.
(I know that morose can be written as sullen)
(Other definitions for sullen that I've seen before include "Glowering silently" , "Morose and resentful" , "Gloomy and resentful" , "Angrily silent" , "Sulkily bad-tempered" .)