Angry expression (5)
(Other definitions for glare that I've seen before include "Stare fiercely - 5 down (anag)" , "Dazzling light (of publicity?)" , "Too-bright light" , "Large (anag.)" , "Angry look" .)
'angry expression' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for scowl that I've seen before include "Bad-tempered expression" , "Glower; frown" , "Angry frown" , "Look threatening" , "Gloomy or threatening expression" .)