A uniform colour perhaps (5)
I believe the answer is:
khaki
This could be a double definition.
'a uniform' is the first definition.
(I've seen this before)
'colour perhaps' is the second definition.
'khaki' can be an answer for 'colour' (I have seen 'Military colour' mean 'khaki' so perhaps 'colour' could also mean 'khaki'). I am unsure of the 'perhaps' bit.
Can you help me to learn more?
(Other definitions for khaki that I've seen before include "Army fabric" , "strong fabric" , "Military camouflage colour" , "Army uniform colour" , "Yellowish brown (used by military)" .)