Saintly glow (4)
I believe the answer is:
halo
'saintly glow' 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 "Hagiological aura featured in Christian art" , "Disc of light" , "Glowing ring (around saint's head)" , "Aura representing saintliness" , "Crown" .)