means To briefly close and open one eye as a deliberate signal — of flirtation, complicity, or a joke shared without words.

from From Old English 'wincian,' to close the eyes or blink, sharing deep Germanic roots with Dutch 'winken' and German 'winken' (to wave or beckon) — a family of words about flickering, fluttering gestures. The same root branch gives us 'wince,' that involuntary flinch, hinting that the eye's quick shutting once meant any sudden flicker before it narrowed to one knowing eyelid. The sleep-related sense survives in the phrase 'not a wink,' meaning not even the brief closing of an eye.