Overturn, revoke (6)
I believe the answer is:
repeal
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">overturn</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that overturn can be written as repeal)</span><br/ ><br/ >'<span class="explanation-format__original">revoke</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that revoke can be written as repeal)</span><br/ ><br/ ></span>
(Other definitions for repeal that I've seen before include "reverse" , "Annul a law" , "Cancel or nullify a law" , "Rescind or withdraw a law" , "Annul by legislative action" .)