glare (n.)

c. 1400, "bright light, dazzling glitter," from glare (v.); especially in reference to light reflected off some surface (17c.). From 1660s in sense of "fierce look." Old English glær (n.) meant "amber."

glare (v.)

late 13c., "to shine brightly," from or related to Middle Dutch, Middle Low German glaren "to gleam," from Proto-Germanic *glaz-, from PIE root *ghel- (2) "to shine." Sense of "stare fiercely" is from late 14c. Related: Glared; glaring.