Tiny bite (3)
I believe the answer is:
nip
'tiny bite' 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 "Pinch; drink of spirits" , "Pinch; bite" , "Pinch using pin" , "Small drink of spirits" , "(Give) a small sharp bite" .)