Business admits a transgression — gambling's prevalent here (6)
I believe the answer is:
casino
'gambling's prevalent here' is the definition.
(people gamble in casinos)
'business admits a transgression' is the wordplay.
'business' becomes 'co' (short for company).
'admits' means one lot of letters goes inside another.
'transgression' becomes 'sin' (sin is a kind of transgression).
'a'+'sin'='asin'
'co' placed around 'asin' is 'CASINO'.
(Other definitions for casino that I've seen before include "Gambling establishment" , "gambling joint" , "gambling organisation" , "Gambling emporium" , "that offers better risks" .)