Edith alone has saintly sign (4)
I believe the answer is:
halo
'saintly sign' is the definition.
(I've seen this in another clue)
'edith alone has' is the wordplay.
'has' says the answer is hidden in the clue.
'HALO' can be found hidden inside 'edith alone'.
(Other definitions for halo that I've seen before include "Disc of light" , "Glittering aura" , "Saint's circle of light" , "Circle of light around the moon" , "Holy ring" .)