Third person singular present tense of glower; to look at someone with an angry, threatening expression.
From Middle English glowren, possibly from Old Norse glotta meaning to grin scornfully. The word entered English around the 15th century and has maintained its sense of an intense, dark stare combined with anger or disapproval.
Interestingly, 'glower' and 'glare' are often confused, but glower implies a darker, more brooding intensity—you can glare at something neutral like the sun, but you really need genuine anger to glower properly.
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