noun
gleam in one's eye; sparkle of one's eyes
Refers to the sharp, piercing light or intensity in someone's eyes, often implying strong will, keen perception, or a formidable presence.
彼の眼光は鋭く、相手を威圧した。
The gleam in his eyes was sharp and intimidated the other person.
noun
insight; discernment; power of observation
Figurative extension: the ability to see through things, judge accurately, or perceive hidden truths. Often used in phrases like 眼光紙背に徹す (reading between the lines).
彼の眼光は鋭く、問題の本質をすぐに見抜いた。
His insight was sharp, and he immediately saw through to the heart of the problem.
Compound of 眼 (eye) and 光 (light). The literal meaning 'light of the eyes' naturally extended to the figurative sense of keen perception or insight.