Merriam-Webster's Collegiate® Dictionary, 11th Edition
WINK
I. verb
Etymology: Middle English, from Old English wincian; akin to Old High German winchan to stagger, wink and perhaps to Latin vacillare to sway, Sanskrit vañcati he goes crookedly Date: before 12th century intransitive verb to shut one eye briefly as a signal or in teasing, to close and open the eyelids quickly, to avoid seeing or noting something, to gleam or flash intermittently ; twinkle ,
5. to come to an end, to stop shining, to signal a message with a light, transitive verb to cause to open and shut, to affect or influence by or as if by blinking the eyes,
II. noun
Date: 14th century
a brief period of sleep ; nap ,
2. a hint or sign given by winking, an act of winking, the time of a wink ; instant , a flicker of the eyelids ; blink