Allow, authorise (6)
I believe the answer is:
permit
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">allow</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that allow can be written as permit)</span><br/ ><br/ >'<span class="explanation-format__original">authorise</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that authorise is a more specific form of permit)</span><br/ ><br/ ></span>
(Other definitions for permit that I've seen before include "Allow - visa" , "Let - pass" , "Let; enabling document" , "Allow; make possible" , "Warrant" .)