An eye for an eye (3,3,3)
(Other definitions for vengeance that I've seen before include "Retributory punishment" , "Retribution" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">an eye for an eye</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tit for tat that I've seen before include "reprisal" , "satisfaction" , "revenge" , "protection given to Barnet" , "Retaliation called for" .)