Surfboard flaw (4)
I believe the answer is:
ding
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">surfboard flaw</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 ding that I've seen before include "Sound" , "- - dong" , "Keep sounding" , "-- -a-ling" .)