Officer’s personal servant (6)
I believe the answer is:
batman
'officer's personal servant' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for batman that I've seen before include "Comic strip character" , "Caped crusader of Gotham City, cartoon or cinema" , "Superhero, Robin's partner" , "Caped superhero" , "Comic book hero with Robin as a sidekick" .)