Helps since wager taken in (5)
I believe the answer is:
abets
'helps' is the definition.
(to abet is to aid or assist)
'since wager taken in' is the wordplay.
'since' becomes 'as' (I've seen this in other clues).
'wager' becomes 'bet' (synonyms).
'taken in' means one lot of letters goes inside another.
'as' going around 'bet' is 'ABETS'.
(Other definitions for abets that I've seen before include "Assists in wrongdoing" , "Helps (someone to commit crime)" , "Aids and encourages" , "Gives support" , "Aids in wrong-doing" .)