Meaning

noun an angry stare

verb look at with a fixed gaze

verb look angry or sullen, wrinkle one's forehead, as if to signal disapproval

originFrom an alteration (possibly Scots) of glore, from Middle English glōren, glouren (“to gleam; to glare, glower”); or from glow (“to stare”) (obsolete), and ultimately from a Scandinavian (North Germanic) language. Cognate with Low German gloren (“to flicker; to glimmer”), Dutch gloren, Icelandic glóra. Equivalent to glow + -er (a fossilized frequentative suffix). See more at glare.

Etymology from Wiktionary, CC BY-SA 3.0