Of admirals and warships (5)
I believe the answer is:
naval
'of admirals and warships' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for naval that I've seen before include "Maritime" , "Relating to nautical defence forces" , "Relates to nautical defence force" , "Relating to the Senior Service" , "To do with the marine branch of an army" .)