Ow! (4)
I believe the answer is:
ouch
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ow</span>' is the definition.<br/ ><span class="explanation-format__explanation">(interjection synonym)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ouch that I've seen before include "Ow!" , "sounds painful" , "Shout of pain" , "Pained cry" , "Cry of pain" .)