Chilly air
I believe the answer is:
nip
'chilly air' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nip that I've seen before include "Feeling cold" , "Pinch; drink of spirits" , "Pinch or squeeze sharply" , "A small whisky" , "Pinch, maybe in the bud" .)