Snake sound (4)
I believe the answer is:
hiss
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">snake 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 hiss that I've seen before include "(Make noise to) express disapproval" , "Sibilant sound made through the teeth" , "Snake's sibilant sound" , "Make disapproving sound" , "Audio interference" .)