The Collaborative International Dictionary of English v.0.48:

Shy \Shy\ (sh[imac]), a. [Compar. Shier (sh[imac]"[~e]r) or
   Shyer; superl. Shiest or Shyest.] [OE. schey, skey,
   sceouh, AS. sce['o]h; akin to Dan. sky, Sw. skygg, D. schuw,
   MHG. schiech, G. scheu, OHG. sciuhen to be or make timid. Cf.
   Eschew.]
   1. Easily frightened; timid; as, a shy bird.
      [1913 Webster]

            The horses of the army . . . were no longer shy, but
            would come up to my very feet without starting.
                                                  --Swift.
      [1913 Webster]

   2. Reserved; coy; disinclined to familiar approach.
      [1913 Webster]

            What makes you so shy, my good friend? There's
            nobody loves you better than I.       --Arbuthnot.
      [1913 Webster]

            The embarrassed look of shy distress
            And maidenly shamefacedness.          --Wordsworth.
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   3. Cautious; wary; suspicious.
      [1913 Webster]

            I am very shy of using corrosive liquors in the
            preparation of medicines.             --Boyle.
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            Princes are, by wisdom of state, somewhat shy of
            thier successors.                     --Sir H.
                                                  Wotton.
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   4. Inadequately supplied; short; lacking; as, the team is shy
      two players.[Slang]
      [Webster 1913 Suppl.]

   5. (Poker), owing money to the pot; -- in cases where an
      opponent's bet has exceeded a player's available stake or
      chips, but the player chooses to continue playing the hand
      before adding the required bet to the pot. [Slang]
      [PJC]

   To fight shy. See under Fight, v. i.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shy \Shy\, v. i. [imp. & p. p. Shied; p. pr. & vb. n.
   Shying.] [From Shy, a.]
   To start suddenly aside through fright or suspicion; -- said
   especially of horses.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shy \Shy\, v. t.
   To throw sidewise with a jerk; to fling; as, to shy a stone;
   to shy a slipper. --T. Hughes.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shy \Shy\, n.
   1. A sudden start aside, as by a horse.
      [1913 Webster]

   2. A side throw; a throw; a fling. --Thackeray.
      [1913 Webster]

            If Lord Brougham gets a stone in his hand, he must,
            it seems, have a shy at somebody.     --Punch.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shy
    adj 1: lacking self-confidence; "stood in the doorway diffident
           and abashed"; "problems that call for bold not timid
           responses"; "a very unsure young man" [syn: diffident,
           shy, timid, unsure] [ant: confident]
    2: short; "eleven is one shy of a dozen"
    3: wary and distrustful; disposed to avoid persons or things;
       "shy of strangers"
    n 1: a quick throw; "he gave the ball a shy to the first
         baseman"
    v 1: start suddenly, as from fright
    2: throw quickly

Moby Thesaurus II by Grady Ward, 1.0:

321 Moby Thesaurus words for "shy":
   Pyrrhonic, about the bush, afraid, agnostic, apprehensive,
   around the bush, arrested, averse, avert, avoid, back down,
   backhanded, backward, balance, balk, bankrupt in, bare of, bashful,
   be startled, bear off, beat about, beat around, beg the question,
   bereft of, bicker, bilk, blench, blink, boggle, boggling, bowl,
   cagey, callow, cast, cast at, catapult, cautious, cavil, chary,
   choplogic, chuck, chuck at, chunk, circumspect, confused,
   conscious, cowardly, coy, cringe, dart, dash, debate, defective,
   deficient, deliberate, demur, demure, demurring, denuded of,
   deprived of, destitute of, devoid of, diffident, distrustful,
   dodge, double, doubtful, doubting, draw aside, draw back, draw in,
   dubious, duck, ease off, edge off, elude, embryonic, empty of,
   equivocate, eschew, evade, evade the issue, fade, failing,
   fall back, falter, faltering, fear, fearful, fearing, fearsome,
   fence, fight shy, fight shy of, fire, fire at, flinch, fling,
   fling at, flip, fly off, for want of, fork, forlorn of,
   from Missouri, gag, gee, glance, glance off, go off, goosy,
   hang back, hang off, have qualms, haw, head off, heave, heave at,
   hedge, hem and haw, hesitant, hesitate, hesitating, hold off,
   hover, hum and haw, hurl, hurl against, hurl at, hurtle,
   hypoplastic, immature, in arrear, in arrears, in default,
   in default of, in doubt, in fear, in short supply, in want of,
   inadequate, inarticulate, incomplete, indisposed, infant,
   insufficient, introversive, introvert, introverted, jerk, jib,
   jump, jump a mile, jumpy, lacking, lance, launch, leery, let fly,
   let fly at, loath, lob, make bones about, make way for, missing,
   mistrustful, mistrusting, modest, mousy, move aside, mystify,
   needing, nervous, nitpick, obscure, out of, out of pocket, palter,
   panic, parry, part, partial, pass, patchy, pause, peg, pelt,
   pick nits, pitch, pitchfork, ponder, pot, prevaricate, pull away,
   pull back, pull in, pull out, pussyfoot, put, put off,
   put the shot, quail, qualmish, questioning, quibble, rabbity,
   recoil, reel back, reluctant, reserved, retiring, retract, retreat,
   scant, scant of, scanty, scarce, scary, scrappy, scruple,
   scrupulous, self-conscious, self-distrustful, self-effacing, serve,
   shaky, shamefaced, shamefast, sheepish, sheer off, shift,
   shift off, shilly-shally, shivery, short, short of, shove aside,
   shrink, shrink back, shrinking, shuffle, shun, shunt, shy at,
   shy away, shy of, shy off, side, sidestep, sideswipe, sidetrack,
   sidle, skedaddle, skeptical, sketchy, skittery, skittish, sling,
   sling at, snap, split hairs, squeamish, stammering, stampede,
   start, start aside, start back, startle, startlish, steer clear of,
   step aside, stick, stick at, stickle, stickling, stop to consider,
   straddle the fence, strain, strain at, stumble, suspecting,
   suspicious, swerve, switch, tergiversate, think twice about, throw,
   throw at, tilt, timid, timorous, toss, toss at, trembling,
   tremulous, trepidant, trigger-happy, turn aside, turn away,
   turn back, unassertive, unassured, unblessed with, uncertain,
   underdeveloped, undeveloped, uneager, unpossessed of, untrusting,
   unwilling, veer off, void of, wanting, ward off, wary, waver,
   weasel, weasel out, wince, withdraw, yield