Fascinating aura (8)
I believe the answer is:
mystique
'fascinating aura' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mystique that I've seen before include "Glamorous air" , "Enigmatic or compelling quality possessed by a person" , "Magical aura" , "Aura or secrecy or obscurity" , "something inexpressible" .)