Bolt to run smoothly making comeback (4)
I believe the answer is:
wolf
'bolt' is the definition.
(both can mean to eat something quickly)
'run smoothly making comeback' is the wordplay.
'run smoothly' becomes 'flow' (I've seen this before).
'making comeback' says the letters should be written in reverse.
'flow' in reverse letter order is 'WOLF'.
'to' is the link.
(Other definitions for wolf that I've seen before include "character of Prokofiev's music" , "Lupine mammal" , "Austrian composer" , "Predator that hunts in packs" , "Pack hunter" .)