Counsel commercial immorality (6)
I believe the answer is:
advice
'counsel' is the definition.
(thesaurus)
'commercial immorality' is the wordplay.
'commercial' becomes 'ad'.
'immorality' becomes 'vice' (vice is a kind of immorality).
'ad'+'vice'='ADVICE'
(Other definitions for advice that I've seen before include "Admonition" , "Opinion given about what to do" , "Formal notice" , "Supposedly wise words" , "Warning - guidance" .)