Saintly ring (4)
I believe the answer is:
halo
'saintly ring' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for halo that I've seen before include "Ring of light (signifying holiness)" , "Angelic aura" , "Sign of sainthood" , "Holy ring" , "Luminous ring" .)