Brief blast of wind (4)
I believe the answer is:
gust
'brief blast of wind' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gust that I've seen before include "Burst of strong wind" , "A strong current of air" , "Brief rush of wind" , "Blast of air" , "Sudden rush of wind" .)