Deed used in legal battle (6)
I believe the answer is:
action
This might be a double definition.
'deed' is the first definition.
(I've seen this before)
'legal battle' is the second definition.
'action' can be an answer for 'battle' (military action). I am unsure of the 'legal' bit.
'used in' acts as a link.
Can you help me to learn more?
(Other definitions for action that I've seen before include "Not CIA (anag)" , "Deed or legal proceeding" , "exploit" , "''. . . . . . speaks louder than words'' (6)" , "Operation; engagement" .)