Sternutation (6)
I believe the answer is:
sneeze
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sternutation</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 sneeze that I've seen before include "Involuntary expiration of air" , "What might occasion a "Gesundheit"" , "Inadvertent explosion of air" , "Sternutation- see Zen (anag)" , "symptom of flu" .)