Huff and puff
I believe the answer is:
pant
'huff and puff' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pant that I've seen before include "Breathe hard" , "Breathe heavily" , "Sound out of breath" , "Gasp for breath (like a hot dog?)" , "Breathe noisily after running" .)