The Collaborative International Dictionary of English v.0.48:

Outlandish \Out*land"ish\, a. [AS. [=u]tlendisc foreign. See
   Out, Land, and -ish.]
   1. Foreign; not native. [archaic]
      [1913 Webster]

            Him did outlandish women cause to sin. --Neh. xiii.
                                                  26.
      [1913 Webster]

            Its barley water and its outlandish wines. --G. W.
                                                  Cable.
      [1913 Webster]

   2. Hence: Deviating conspicuously from common practice;
      strange; freakish; bizarre; rude; barbarous; uncouth;
      clownish; as, an outlandish dress, behavior, or speech; --
      usually used in a negative sense.
      [1913 Webster +PJC]

            Something outlandish, unearthy, or at variance with
            ordinary fashion.                     --Hawthorne.
      [1913 Webster] --Out*land"ish*ly, adv.
      [1913 Webster]

WordNet (r) 3.0 (2006):

outlandish
    adj 1: conspicuously or grossly unconventional or unusual;
           "restaurants of bizarre design--one like a hat, another
           like a rabbit"; "famed for his eccentric spelling"; "a
           freakish combination of styles"; "his off-the-wall
           antics"; "the outlandish clothes of teenagers"; "outre
           and affected stage antics" [syn: bizarre, eccentric,
           freakish, freaky, flaky, flakey, gonzo, off-
           the-wall, outlandish, outre]

Moby Thesaurus II by Grady Ward, 1.0:

189 Moby Thesaurus words for "outlandish":
   Doric, Gothic, Neanderthal, absurd, alien, animal, apart, back,
   barbarian, barbaric, barbarous, baroque, beguiling, bestial,
   bewildering, bizarre, brain-born, brutal, brutish, cacophonous,
   campy, clumsy, coarse, crude, curious, detached, different,
   disconnected, discrete, disjunct, disrelated, dissociated,
   doggerel, dream-built, dysphemistic, eccentric, enigmatic,
   exceptional, exotic, exterior, external, exterrestrial,
   exterritorial, extragalactic, extralateral, extraliminal,
   extramundane, extramural, extraneous, extraordinary, extrapolar,
   extraprovincial, extrasolar, extraterrestrial, extraterritorial,
   extratribal, extravagant, extrinsic, fabulous, fanciful,
   fancy-born, fancy-built, fancy-woven, fantasque, fantastic,
   fascinating, florid, foreign, foreign-born, freaked out, freakish,
   freaky, frontier, funny, graceless, gross, grotesque, harsh,
   ill-bred, impolite, improper, impure, in bad taste,
   incommensurable, incomparable, incomprehensible, inconceivable,
   inconcinnate, inconcinnous, incorrect, incredible, indecorous,
   independent, inelegant, infelicitous, insular, intrusive,
   irrelative, isolated, kinky, kooky, low, maggoty, marvelous,
   miraculous, monstrous, noncivilized, notional, odd, oddball, off,
   off the wall, offbeat, other, out, outland, outrageous, outre,
   outside, passing strange, peculiar, phenomenal, preposterous,
   primitive, prodigious, puzzling, quaint, queer, rare, remarkable,
   remote, removed, rococo, rough-and-ready, rude, savage, segregate,
   sensational, separate, separated, singular, strange, striking,
   stupendous, tasteless, troglodytic, ulterior, ultra, unaffiliated,
   unallied, unassociated, uncivil, uncivilized, uncombed,
   unconnected, unconventional, uncourtly, uncouth, uncultivated,
   uncultured, undignified, unearthly, uneuphonious, unfamiliar,
   unfelicitous, ungraceful, unheard-of, unimaginable, unique,
   unkempt, unknown, unlicked, unorthodox, unpolished, unprecedented,
   unrefined, unrelatable, unrelated, unseemly, unsettled, untamed,
   unusual, vulgar, weird, whimsical, wild, wonderful, wondrous,
   wondrous strange