Instruments of war (4)
I believe the answer is:
arms
'instruments of war' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for arms that I've seen before include "Provides with weapons" , ". . . . and The Man (G.B. Shaw)" , "pacifists won't take up" , "Supplies weapons" , "military equipment" .)