Battered troopers capturing island back (9)
I believe the answer is:
posterior
'back' is the definition.
(associated in meaning)
'battered troopers capturing island' is the wordplay.
'battered' indicates anagramming the letters.
'capturing' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'troopers' is an anagram of 'posteror'.
'posteror' placed around 'i' is 'POSTERIOR'.
(Other definitions for posterior that I've seen before include "Further back; bottom" , "Rear" , "later" , "Behind" , "Hindquarters" .)