Angelic light (4)
I believe the answer is:
halo
'angelic light' 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 "Sign of sainthood" , "Disc of light" , "that could make one light-headed?" , "Ring (around sun or moon)" , "overhead lighting?" .)