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 present in the answer.
The remaining letters 'ter' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
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" .)