Gambler cured (6)
I believe the answer is:
better
This clue is a double definition.
'gambler' is the first definition.
(better is a kind of gambler)
'cured' is the second definition.
(I've seen this before)
(Other definitions for better that I've seen before include "One making wager; more advantageous" , "Partly or fully recovered from illness" , "cap" , "he will take risks" , "Superior of two alternatives" .)