Absence of sound (7)
I believe the answer is:
silence
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">absence of sound</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 silence that I've seen before include "Quietude" , "Lack of sound" , "Soundlessness" , "License (anag)" , "No talking" .)