Blue, dejected (3)
I believe the answer is:
low
I believe this is a double definition.
'blue' is the first definition.
(I've seen this in another clue)
'dejected' is the second definition.
(similar in meaning)
(Other definitions for low that I've seen before include "Moo; not high" , "Depressed or base" , "Make a bovine sound" , "sound from Hereford?" , "Inferior; moo" .)