Prize in conflict secured by Communist (6)
I believe the answer is:
reward
'prize' is the definition.
(a prize may be given as a reward)
'conflict secured by communist' is the wordplay.
'conflict' becomes 'war' (war is a kind of conflict).
'secured by' is an insertion indicator (inserted letters are held or secured).
'communist' becomes 'red' (red can informally mean communist).
'war' put within 'red' is 'REWARD'.
'in' acts as a link.
(Other definitions for reward that I've seen before include "Drawer (anag.)" , "Payment in appreciation" , "Reinforcement for good behaviour" , "Recompense for worthy act" , "Deserts" .)