Gradually withdraw (4)
I believe the answer is:
wean
'gradually withdraw' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wean that I've seen before include "new child" , "Get baby off the bottle" , "Win over" , "Gradually bring a baby off suckling" , "Accustom to abstain from a former habit" .)