Gambler leaving richer (6,3)
I believe the answer is:
better off
'richer' is the definition.
(I've seen this before)
'gambler leaving' is the wordplay.
'gambler' becomes 'better' (better is a kind of gambler).
'leaving' becomes 'off' (I've seen this in other clues).
'better'+'off'='BETTER-OFF'
(Other definitions for better off that I've seen before include "Someone setting out for the bookies" , "Richer" , "having lost less" , "in happier financial circumstances" , "with more money" .)