Improved gambler (6)
I believe the answer is:
better
I believe this is a double definition.
'improved' is the first definition.
(similar in meaning)
'gambler' is the second definition.
(someone who makes bets is a gambler)
(Other definitions for better that I've seen before include "More competent - gambler" , "Recovered from illness - more satisfactory" , "no longer sick" , "Reformed" , "Superior; gambler" .)