Gambler has small drink for the wife (6,4)
I believe the answer is:
better half
'the wife' is the definition.
(I've seen this in another clue)
'gambler has small drink' is the wordplay.
'gambler' becomes 'better' (someone who makes bets is a gambler).
'has' is a charade indicator (letters next to each other).
'small drink' becomes 'half' (e.g. a half pint).
'better'+'half'='BETTER HALF'
'for' acts as a link.
(Other definitions for better half that I've seen before include "Spouse (informal)" , "Wife (colloq.)" , "partner" , "Husband" , "One's spouse" .)