The Collaborative International Dictionary of English v.0.48:

Wink \Wink\, v. i. [imp. & p. p. Winked; p. pr. & vb. n.
   Winking.] [OE. winken, AS. wincian; akin to D. wenken, G.
   winken to wink, nod, beckon, OHG. winchan, Sw. vinka, Dan.
   vinke, AS. wancol wavering, OHG. wanchal wavering, wanch?n to
   waver, G. wanken, and perhaps to E. weak; cf. AS. wincel a
   corner. Cf. Wench, Wince, v. i.]
   [1913 Webster]
   1. To nod; to sleep; to nap. [Obs.] "Although I wake or
      wink." --Chaucer.
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   2. To shut the eyes quickly; to close the eyelids with a
      quick motion.
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            He must wink, so loud he would cry.   --Chaucer.
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            And I will wink, so shall the day seem night.
                                                  --Shak.
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            They are not blind, but they wink.    --Tillotson.
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   3. To close and open the eyelids quickly; to nictitate; to
      blink.
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            A baby of some three months old, who winked, and
            turned aside its little face from the too vivid
            light of day.                         --Hawthorne.
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   4. To give a hint by a motion of the eyelids, often those of
      one eye only.
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            Wink at the footman to leave him without a plate.
                                                  --Swift.
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   5. To avoid taking notice, as if by shutting the eyes; to
      connive at anything; to be tolerant; -- generally with at.
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            The times of this ignorance God winked at. --Acts
                                                  xvii. 30.
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            And yet, as though he knew it not,
            His knowledge winks, and lets his humors reign.
                                                  --Herbert.
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            Obstinacy can not be winked at, but must be subdued.
                                                  --Locke.
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   6. To be dim and flicker; as, the light winks.
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   Winking monkey (Zool.), the white-nosed monkey
      (Cersopithecus nictitans).
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WordNet (r) 3.0 (2006):

winking
    adj 1: closing the eyes intermittently and rapidly; "he stood
           blinking in the bright sunlight" [syn: blinking,
           winking]
    n 1: a reflex that closes and opens the eyes rapidly [syn:
         blink, eye blink, blinking, wink, winking,
         nictitation, nictation]