"Gesundheit" elicitor (5)
'gesundheit elicitor' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sneeze that I've seen before include "Prelude to Bless you!" , "reason for blessing" , "Involuntary expiration of air" , "Expel air from nose" , "Sign of a cold or flu" .)