Officer's gear sent for repair (8)
I believe the answer is:
sergeant
'officer's' is the definition.
(sergeant is a kind of officer)
'gear sent for repair' is the wordplay.
'for repair' indicates an anagram (I've seen this in other clues).
'gear'+'sent'='gearsent'
'gearsent' is an anagram of 'SERGEANT'.
(Other definitions for sergeant that I've seen before include "Rank above corporal" , "Military or police officer" , "CARRY ON FILM" , "one with stripes" , "Army rank" .)