Bolt to glide smoothly when lifted (4)
I believe the answer is:
wolf
'bolt' is the definition.
(both can mean to eat something quickly)
'glide smoothly when lifted' is the wordplay.
'glide smoothly' becomes 'flow'.
'when lifted' says the letters should be written in reverse (in a down clue, letters go up).
'flow' back-to-front is 'WOLF'.
'to' is the link.
(Other definitions for wolf that I've seen before include "Predatory canine (or man?)" , "Pack-hunting carnivore" , "Lothario" , "Pack animal; composer" , "gorge" .)