Caspar, Melchior and Balthazar (4)
'caspar melchior and balthazar' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for magi that I've seen before include "Travellers in NT" , "Bearers of gold, frankincense and myrrh?" , "Caspar, Melchior and Balthasar" , "The three Wise Men of Bethlehem" , "Priests" .)
(Other definitions for wise men that I've seen before include "Astrologers" , "people up for spells?" , "Bethlehem visitors" , "Magi" .)