Gloriole (4)
I believe the answer is:
halo
'gloriole' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for halo that I've seen before include "Luminous sign of saintliness" , "Glowing ring (around saint's head)" , "glory" , "Angelic aura" , "Light around sun, saint" .)