Sound of a sneeze (7)
I believe the answer is:
atishoo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sound of a sneeze</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for atishoo that I've seen before include "Sudden eruption" , "Sneezing sound" , "report of involuntary escape from trap?" , "Sound of explosion" , "Sound of a sneeze" .)