Heathen silver found in pot (5)
I believe the answer is:
pagan
'heathen' is the definition.
(both can mean an irreligious person)
'silver found in pot' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'found in' indicates putting letters inside.
'pot' becomes 'pan' (I've seen this in other clues).
'ag' put into 'pan' is 'PAGAN'.
(Other definitions for pagan that I've seen before include "One who does not acknowledge your god(s)" , "One who follows a polytheistic or pre-Christian religion, but not a Jew" , "Non-mainstream religious believer" , "Infidel" , "Heathen; non-believer" .)