Pay left-winger for bet (7)
I believe the answer is:
wagered
'for bet' is the definition.
(I've seen this before)
'pay left-winger' is the wordplay.
'pay' becomes 'wage' (synonyms).
'left-winger' becomes 'red' (red is a kind of left-winger).
'wage'+'red'='WAGERED'
(Other definitions for wagered that I've seen before include "Placed a bet" , "Gambled" , "Staked money" , "Made a bet" , "Laid down" .)