Wet slapping sound (5)
I believe the answer is:
splat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wet slapping sound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for splat that I've seen before include "Piece of wood in a chair back" , "Sound of a wet and squishy impact" , "Wet slapping sound" , "Noise on landing" , "Noise of soft wet impact; part of a chair back" .)