Not trained for return battle (3)
I believe the answer is:
raw
'not trained' is the definition.
(I've seen this in another clue)
'return battle' is the wordplay.
'return' says the letters should be written in reverse.
'battle' becomes 'war' (I've seen this before).
'war' written backwards gives 'RAW'.
'for' acts as a link.
(Other definitions for raw that I've seen before include "Uncooked; immature" , "Callow" , "Abraded" , "Not cooked" , "Bleeding" .)