Arthurian wizard (6)
I believe the answer is:
merlin
'arthurian wizard' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for merlin that I've seen before include "Small falcon; Arthur's friend" , "Small falcon; wizard" , "Legendary magician" , "Arthur's adviser" , "Arthurian wizard" .)