Nothing to salute in officers' camp? (5)
I believe the answer is:
oflag
'officers' camp?' is the definition.
(historical German prison camp)
'nothing to salute' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'to salute' becomes 'flag' (I can't justify this - if you can you should believe this answer much more).
'o'+'flag'='OFLAG'
'in' is the link.
(Other definitions for oflag that I've seen before include "Colditz, for example" , "Place of internment" , "prison camp" , "German PoW camp for officers" , "German prisoner of war camp for officers" .)