Introduce to solid food (4)
I believe the answer is:
wean
'introduce to solid food' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for wean that I've seen before include "Accustom baby to take food instead of milk" , "Gradually deprive the young of its mother's milk" , "Gradually bring a baby off suckling" , "Win over" , "Introduce to solid food" .)