Civilian dress (5)
I believe the answer is:
mufti
'civilian dress' is the definition.
(I know that mufti is a type of civilian dress)
This is the entire clue.
(Other definitions for mufti that I've seen before include "Civvies; Muslim legal expert" , "Civilian dress, worn by an off-duty soldier, say" , "No official dress" , "Plain clothes - Muslim law expert" , "Civilian clothing for a military person" .)