A risk to run as accomplice (7)
I believe the answer is:
abettor
'accomplice' is the definition.
(abettor is a kind of accomplice)
'a risk to run' is the wordplay.
'risk' becomes 'bet'.
'run' becomes 'r' (cricket abbreviation).
'a'+'bet'+'to'+'r'='ABETTOR'
'as' is the link.
(Other definitions for abettor that I've seen before include "Accomplice" , "One who helps" , "one to encourage or help" , "Associate" , "One aids another" .)