Set free; loosen (5)
I believe the answer is:
untie
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">set free</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">loosen</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that loosen can be written as untie)</span><br/ ><br/ ></span>
(Other definitions for untie that I've seen before include "resolve" , "Detach" , "Free from restraining bonds or ropes" , "Loose bonds" , "Remove ropes, unfasten" .)