Weekend warrior, perhaps (9)
I believe the answer is:
reservist
'weekend warrior perhaps' is the definition.
(I know that weekend warrior is a type of reservist)
This is the entire clue.
(Other definitions for reservist that I've seen before include "militia member" , "one of 51 [THETA] ?" , "Eg, a TA member" , "Soldier able to be called up" , "Soldier called up when needed" .)