Magic Circle minister (6)
I believe the answer is:
cleric
'minister' is the definition.
(thesaurus)
'magic circle' is the wordplay.
'magic' is an anagram indicator.
'circle' is an anagram of 'CLERIC'.
(Other definitions for cleric that I've seen before include "Divine" , "Ordained minister" , "Religious official" , "Man of the cloth" , "Person in holy orders" .)