Coming back unprepared for conflict (3)
I believe the answer is:
war
'conflict' is the definition.
(war is a kind of conflict)
'coming back unprepared' is the wordplay.
'coming back' says the letters should be written backwards.
'unprepared' becomes 'raw'.
'raw' backwards is 'WAR'.
'for' acts as a link.
(Other definitions for war that I've seen before include "Sustained conflict" , "Armed hostility" , "Fight" , "Period of hostilities" , "series of engagements" .)