[syn: fantastic, fantastical]
5.  extravagantly fanciful in design, construction, appearance; 
- Example: "Gaudi's fantastic architecture"
The Collaborative International Dictionary of English v.0.48:
Fantastic \Fan*tas"tic\, n.
   A person given to fantastic dress, manners, etc.; an
   eccentric person; a fop. --Milton.
   [1913 Webster]
         Our fantastics, who, having a fine watch, take all
         ocasions to draw it out to be seen.      --Fuller.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Fantastic \Fan*tas"tic\, a. [F. fantastique, fr. Gr. ???????????
   able to represent, fr. ????????? to make visible. See
   Fancy.]
   1. Existing only in imagination; fanciful; imaginary; not
      real; chimerical.
      [1913 Webster]
   2. Having the nature of a phantom; unreal. --Shak.
      [1913 Webster]
   3. Indulging the vagaries of imagination; whimsical; full of
      absurd fancies; capricious; as, fantastic minds; a
      fantastic mistress.
      [1913 Webster]
   4. Resembling fantasies in irregularity, caprice, or
      eccentricity; irregular; oddly shaped; grotesque.
      [1913 Webster]
            There at the foot of yonder nodding beech,
            That wreathes its old fantastic roots so high. --T.
                                                  Gray.
   Syn: Fanciful; imaginative; ideal; visionary; capricious;
        chimerical; whimsical; queer. See Fanciful.
        [1913 Webster]
WordNet (r) 3.0 (2006):
fantastic
    adj 1: ludicrously odd; "Hamlet's assumed antic disposition";
           "fantastic Halloween costumes"; "a grotesque reflection
           in the mirror" [syn: antic, fantastic, fantastical,
           grotesque]
    2: extraordinarily good or great ; used especially as
       intensifiers; "a fantastic trip to the Orient"; "the film was
       fantastic!"; "a howling success"; "a marvelous collection of
       rare books"; "had a rattling conversation about politics"; "a
       tremendous achievement" [syn: fantastic, grand,
       howling(a), marvelous, marvellous, rattling(a),
       terrific, tremendous, wonderful, wondrous]
    3: fanciful and unrealistic; foolish; "a fantastic idea of his
       own importance" [syn: fantastic, wild]
    4: existing in fancy only; "fantastic figures with bulbous heads
       the circumference of a bushel"- Nathaniel Hawthorne [syn:
       fantastic, fantastical]
    5: extravagantly fanciful in design, construction, appearance;
       "Gaudi's fantastic architecture"
Moby Thesaurus II by Grady Ward, 1.0:
194 Moby Thesaurus words for "fantastic":
   Barmecidal, Barmecide, Gothic, absurd, adroit, airy, alien, antic,
   appalling, apparent, apparitional, arbitrary, astonishing,
   autistic, balmy, baroque, beguiling, bewildering, beyond belief,
   bizarre, brain-born, capricious, chimeric, chimerical, clever,
   cockamamie, concocted, conspicuous, cooked-up, cracking, cranky,
   crazy, crotchety, deceptive, delusional, delusionary, delusive,
   delusory, dereistic, dream-built, dreamlike, dreamy, eccentric,
   egregious, enigmatic, erratic, erroneous, exceptional, exotic,
   extraordinary, extravagant, fabricated, fabulous, fallacious,
   false, fancied, fanciful, fancy-born, fancy-built, fancy-woven,
   fantasied, fantasque, fascinating, fictional, fictitious, fictive,
   figmental, flaky, florid, foolish, forged, formidable, freakish,
   great, grotesque, harebrained, hatched, high-flown, humorsome,
   illusional, illusionary, illusive, illusory, imaginary, imagined,
   implausible, impossible, incomprehensible, inconceivable,
   incredible, ingenious, insane, invented, irrational, kinky,
   laughable, legendary, loony, ludicrous, made-up, maggoty,
   manufactured, marked, marvelous, massive, miraculous, misleading,
   monstrous, monumental, moody, mortal, motiveless, mythical,
   nonsensical, notable, noteworthy, noticeable, notional, odd,
   of mark, ostensible, outlandish, outrageous, outre, outstanding,
   overwhelming, passing strange, peculiar, petulant, phantasmagoric,
   phantasmal, phantom, phenomenal, poppycockish, preposterous,
   prodigious, put-up, puzzling, quaint, queer, quirky, rare,
   remarkable, ridiculous, rococo, seeming, self-deceptive,
   self-deluding, sensational, signal, silly, singular, specious,
   spectacular, spectral, splendid, strange, striking, stupendous,
   superior, supposititious, temperamental, terrific, towering,
   tremendous, trumped-up, unaccountable, unactual, unbelievable,
   uncommon, unearthly, unexpected, unfounded, unheard-of,
   unimaginable, unique, unlikely, unprecedented, unreal, unrealistic,
   unreasonable, unrestrained, unsubstantial, vagarious, vagrant,
   visionary, wacky, wanton, wayward, weird, whimsical, wild,
   wonderful, wondrous