Run out (6)
I believe the answer is:
expire
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">run out</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that run out can be written as expire)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for expire that I've seen before include "Run out (of time?)" , "Die, give out" , "Lose validity" , "Come to an end; die" , "Die or go out of date" .)