The Collaborative International Dictionary of English v.0.48:

Antic \An"tic\, v. i.
   To perform antics.
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The Collaborative International Dictionary of English v.0.48:

Antic \An"tic\ ([a^]n"t[i^]k), a. [The same word as antique; cf.
   It. antico ancient. See Antique.]
   1. Old; antique. (Zool.) "Lords of antic fame." --Phaer.
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   2. Odd; fantastic; fanciful; grotesque; ludicrous.
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            The antic postures of a merry-andrew. --Addison.
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            The Saxons . . . worshiped many idols, barbarous in
            name, some monstrous, all antic for shape. --Fuller.
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The Collaborative International Dictionary of English v.0.48:

Antic \An"tic\, n.
   1. A buffoon or merry-andrew; one that practices odd
      gesticulations; the Fool of the old play.
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   2. An odd imagery, device, or tracery; a fantastic figure.
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            Woven with antics and wild imagery.   --Spenser.
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   3. A grotesque trick; a piece of buffoonery; a caper.
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            And fraught with antics as the Indian bird
            That writhes and chatters in her wiry cage.
                                                  --Wordsworth.
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   4. (Arch.) A grotesque representation. [Obs.]
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   5. An antimask. [Obs. or R.]
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            Performed by knights and ladies of his court
            In nature of an antic.                --Ford.
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The Collaborative International Dictionary of English v.0.48:

Antic \An"tic\, v. t. [imp. & p. p. Anticked, Antickt.]
   To make appear like a buffoon. [Obs.] --Shak.
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The Collaborative International Dictionary of English v.0.48:

Antique \An*tique"\, a. [F., fr. L. antiquus old, ancient,
   equiv. to anticus, from ante before. Cf. Antic.]
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   1. Old; ancient; of genuine antiquity; as, an antique statue.
      In this sense it usually refers to the flourishing ages of
      Greece and Rome.
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            For the antique world excess and pride did hate.
                                                  --Spenser.
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   2. Old, as respects the present age, or a modern period of
      time; of old fashion; antiquated; as, an antique robe.
      "Antique words." --Spenser.
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   3. Made in imitation of antiquity; as, the antique style of
      Thomson's "Castle of Indolence."
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   4. Odd; fantastic. [In this sense, written antic.]
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   Syn: Ancient; antiquated; obsolete; antic; old-fashioned;
        old. See Ancient.
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WordNet (r) 3.0 (2006):

antic
    adj 1: ludicrously odd; "Hamlet's assumed antic disposition";
           "fantastic Halloween costumes"; "a grotesque reflection
           in the mirror" [syn: antic, fantastic, fantastical,
           grotesque]
    n 1: a ludicrous or grotesque act done for fun and amusement
         [syn: antic, joke, prank, trick, caper, put-on]
    v 1: act as or like a clown [syn: clown, clown around,
         antic]

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "antic":
   animated, artifice, bizarre, caper, capersome, caracole, carry on,
   casual, cavort, coltish, comic, comical, curvet, cut a dido,
   cut capers, cut up, dance, disport, easy, exuberant, fanciful,
   fantastic, farcical, flounce, fool around, foolish, frisk, frisky,
   frolic, frolicsome, full of beans, gambol, gamesome, gay,
   grotesque, hearty, horse around, impossible, incomprehensible,
   inconceivable, incredible, lark, laughable, light, lively,
   ludicrous, mischievous, monkeyshine, monkeyshines, play, playful,
   practical joke, prank, prankish, pranky, roguish, rollick,
   rollicking, rollicksome, romp, rompish, shenanigan, shenanigans,
   shines, skip, skittish, spirited, sport, sportive, sprightly,
   suave, tomfoolery, trick, trip, unaccountable, unbelievable,
   unexpected, unimaginable, vital, vivacious, waggish trick,
   whimsical, wile, zestful, zippy