'glower' originates from Middle English, specifically the word 'gloren,' where 'gloren' meant 'to stare or look intently.'

'gloren' transformed into the Scots word 'glower,' and eventually became the modern English word 'glower.'

Initially, it meant 'to stare or look intently,' but over time it evolved into its current meaning of 'to look angrily or sullenly.'