Prohibit by law (3)
I believe the answer is:
ban
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prohibit by law</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ban that I've seen before include "Bar, prohibition" , "the calling of young vassals" , "Officially prohibit" , "Exile" , "Embargo" .)