Source : Webster's Revised Unabridged Dictionary (1913)

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.]
   1. To nod; to sleep; to nap. [Obs.] ``Although I wake or
      wink.'' --Chaucer.

   2. To shut the eyes quickly; to close the eyelids with a
      quick motion.

            He must wink, so loud he would cry.   --Chaucer.

            And I will wink, so shall the day seem night.
                                                  --Shak.

            They are not blind, but they wink.    --Tillotson.

   3. To close and open the eyelids quickly; to nictitate; to
      blink.

            A baby of some three months old, who winked, and
            turned aside its little face from the too vivid
            light of day.                         --Hawthorne.

   4. To give a hint by a motion of the eyelids, often those of
      one eye only.

            Wink at the footman to leave him without a plate.
                                                  --Swift.

   5. To avoid taking notice, as if by shutting the eyes; to
      connive at anything; to be tolerant; -- generally with at.

            The times of this ignorance God winked at. --Acts
                                                  xvii. 30.

            And yet, as though he knew it not, His knowledge
            winks, and lets his humors reign.     --Herbert.

            Obstinacy can not be winked at, but must be subdued.
                                                  --Locke.

   6. To be dim and flicker; as, the light winks.

   {Winking monkey} (Zo["o]l.), the white-nosed monkey
      ({Cersopithecus nictitans}).

Wink \Wink\, v. t.
   To cause (the eyes) to wink.[Colloq.]

Wink \Wink\, n.
   1. The act of closing, or closing and opening, the eyelids
      quickly; hence, the time necessary for such an act; a
      moment.

            I have not slept one wink.            --Shak.

            I could eclipse and cloud them with a wink. --Donne.

   2. A hint given by shutting the eye with a significant cast.
      --Sir. P. Sidney.

            The stockjobber thus from Change Alley goes down,
            And tips you, the freeman, a wink.    --Swift.

Source : WordNet®

wink
     n 1: a very short time (as the time it takes the eye blink or the
          heart to beat); "if I had the chance I'd do it in a
          flash" [syn: {blink of an eye}, {flash}, {heartbeat}, {instant},
           {jiffy}, {split second}, {trice}, {twinkling}, {New
          York minute}]
     2: closing one eye quickly as a signal
     3: a reflex that closes and opens the eyes rapidly [syn: {blink},
         {eye blink}, {blinking}, {winking}, {nictitation}, {nictation}]
     v 1: signal by winking; "She winked at him"
     2: gleam or glow intermittently; "The lights were flashing"
        [syn: {flash}, {blink}, {twinkle}, {winkle}]
     3: briefly shut the eyes; "The TV announcer never seems to
        blink" [syn: {blink}, {nictitate}, {nictate}]
     4: force to go away by blinking; "blink away tears" [syn: {blink},
         {blink away}]