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 an anagram.
'capturing' indicates putting letters inside.
'island' becomes 'i' (geographical abbreviation).
'troopers' is an anagram of 'posteror'.
'posteror' going around 'i' is 'POSTERIOR'.
(Other definitions for posterior that I've seen before include "Further back; bottom" , "Rear" , "later" , "Behind" , "Hindquarters" .)