Be holding it and get a nip from (4)
I believe the answer is:
bite
'get a nip from' is the definition.
I can't tell whether this defines the answer.
'be holding it' is the wordplay.
'holding' is an insertion indicator.
'be' enclosing 'it' is 'BITE'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for bite that I've seen before include "Light meal" , "(Of fish) take the bait" , "power" , "Quick snack" , "Injury from teeth" .)