Penal; retaliatory (8)
I believe the answer is:
punitive
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">penal</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">retaliatory</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for punitive that I've seen before include "Inflicting penalties" , "As deterrent, retribution" , "Penal; crippling" , "Severe and retaliatory" , "intended to teach a lesson" .)