Act of retaliation (3,3,3)
'act of retaliation' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for reprisal that I've seen before include "hitting back" , "compensation" , "Counterattack" , "Retaliatory action against an enemy" , "revenge attack" .)
(Other definitions for revenge that I've seen before include "Retribution" , "Malicious retaliation" , "An eye for an eye" , "Ship remembered in verse" , "Satisfaction taken for injury" .)
(Other definitions for vengeance that I've seen before include "Retribution" , "Retributory punishment" .)
(Other definitions for tit for tat that I've seen before include "You hit me, I hit you" , "In annoyance, return" , "An eye for an eye" , "Repayment in kind" , "Retaliation in kind" .)