expression
with one's eyes flashing; with a fierce glare
A literary set phrase describing an intense, determined, or angry expression where the eyes are wide open and glaring. Often used in dramatic or narrative contexts.
彼は眦を決して敵をにらみつけた。
He glared at his enemy with flashing eyes.
睨む is a common verb meaning 'to glare at' or 'to stare fiercely,' while 眦を決して is a more intense, literary expression emphasizing the flashing or determined look in the eyes.
The phrase combines 眦 (まなじり, 'corner of the eye' or 'glare') with 決して (けっして, the -te form of 決する, 'to decide' or 'to resolve'), literally meaning 'with the eyes resolved.' The exact historical derivation is uncertain, but it is a fixed literary expression.