Prepares for battle (4)
I believe the answer is:
arms
'prepares for battle' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for arms that I've seen before include "Shaw wrote play '. . . . and the Man'" , "Blazonry; weaponry" , "Weapons and limbs" , "military equipment" , "Heraldic devices" .)