Who places wager with more success (6)
I believe the answer is:
better
'success' is the definition.
(thesaurus)
'who places wager with more' is the wordplay.
I cannot quite understand how this works, but
'wager' could be 'bet' (synonyms) and 'bet' is found within the answer.
The remaining letters 'ter' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for better that I've seen before include "One may lay" , "layer" , "Comparatively good" , "Gambler; more effective" , "M ore appropriate" .)