The Collaborative International Dictionary of English v.0.48:

Outr'e \Ou`tr['e]"\, a. [F., p.p. of outer to exaggerate, fr. L.
   ultra beyond. See Outrage.]
   Out of the common course or limits; extravagant[2]; bizarre;
   outlandish[2]; as, an outr['e] costume.
   [Webster 1913 Suppl. + PJC]

         My first mental development had in it much of the
         uncommon -- even much of the outr['e].   --E. A. Poe.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

outre
    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:

31 Moby Thesaurus words for "outre":
   absurd, beyond belief, bizarre, cockamamie, crazy, extravagant,
   fantastic, foolish, freakish, grotesque, high-flown, incredible,
   kinky, laughable, ludicrous, monstrous, nonsensical, odd,
   out-of-the-way, outlandish, outrageous, peculiar, poppycockish,
   preposterous, ridiculous, strange, ultra, unconventional, unusual,
   weird, wild