Start to eat after little nibble (4)
I believe the answer is:
bite
'nibble' is the definition.
(I've seen this before)
'start to eat after little' is the wordplay.
'start to' indicates taking the first letters.
'after' is a charade indicator (letters next to each other).
'little' becomes 'bit' (I've seen this in other clues).
The first letter of 'eat' is 'e'.
'e' put after 'bit' is 'BITE'.
(Other definitions for bite that I've seen before include "The taking of bait by a fish" , "Grip with teeth" , "Morsel" , "Take effect; snack" , "Light meal" .)