Unfasten, remove (6)
I believe the answer is:
detach
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">unfasten</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">remove</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for detach that I've seen before include "Disengage (something) and remove it" , "The reverse of 11 Down" , "Take away -- the cad (anag)" , "Separate, disconnect" , "His timid love song (T. S. Eliot)" .)