Blinding light (5)
I believe the answer is:
glare
'blinding light' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for glare that I've seen before include "Blinding light" , "Shine intensely" , "Stare angrily" , "Scowl angrily" , "Stare fiercely - 5 down (anag)" .)