Breathe in short gasps (4)
I believe the answer is:
puff
'breathe in short gasps' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for puff that I've seen before include "publicity" , "Light pastry; some wind" , "Drag on fag; be out of breath" , "Smoke - light pastry" , "Short burst of wind" .)