Military force (4)
'military force' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for army that I've seen before include "See 7" , "Large number of people" , "See 17" , "Ground forces" , "fighters" .)
(Other definitions for navy that I've seen before include "A dark blue; service" , "Shade of the marine forces" , "Ships-of-war" , "Marine force" , "Dark shade of blue" .)