Heathen deity accepts silver (5)
I believe the answer is:
pagan
'heathen' is the definition.
(both can mean an irreligious person)
'deity accepts silver' is the wordplay.
'deity' becomes 'pan' (Pan is an example).
'accepts' is an insertion indicator.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'pan' enclosing 'ag' is 'PAGAN'.
(Other definitions for pagan that I've seen before include "advocate of pleasures" , "Heathen; non-believer" , "One who follows a polytheistic or pre-Christian religion, but not a Jew" , "One who does not acknowledge your god(s)" , "One who does not acknowledge a god" .)