Fighting back though inexperienced (3)
I believe the answer is:
raw
'inexperienced' is the definition.
(similar in meaning)
'fighting back' is the wordplay.
'fighting' becomes 'war'.
'back' says the letters should be written in reverse.
'war' in reverse letter order is 'RAW'.
'though' acts as a link.
(Other definitions for raw that I've seen before include "Uncooked or sore" , "Untried (of recruit) - uncooked (of meat)" , "Unpleasantly cold and damp" , "Like a recruit" , "Uncooked or unsavoury" .)