Slightest sound (4)
I believe the answer is:
peep
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">slightest sound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for peep that I've seen before include "Palindromic glimpse" , "Look quickly" , "Look secretly" , "Chirp" , "Take quick look" .)