Baby's drink (3)
I believe the answer is:
tot
This clue is a double definition.
'baby's' is the first definition.
(I've seen this in another clue)
'drink' is the second definition.
(a small alcoholic drink)
(Other definitions for tot that I've seen before include "Small baby" , "Add the little child?" , "Tiny child" , "Spirit measure" , "two fingers, perhaps" .)