The Collaborative International Dictionary of English v.0.48:

Unique \U*nique"\, a. [F. unique; cf. It. unico; from L. unicus,
   from unus one. See One.]
   Being without a like or equal; unmatched; unequaled;
   unparalleled; single in kind or excellence; sole. --
   U*nique"ly, adv. -- U*nique"ness, n.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Unique \U*nique"\, n.
   A thing without a like; something unequaled or unparalleled.
   [R.]
   [1913 Webster]

         The phenix, the unique pf birds.         --De Quincey.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

158 Moby Thesaurus words for "unique":
   a certain, absolute, almost unheard-of, alone, an, another, any,
   any one, appropriate, atomic, authentic, avant-garde, azygous,
   beguiling, bewildering, beyond compare, beyond comparison,
   breakaway, celibate, characteristic, creative, different,
   distinctive, distinguished, easily first, either, else, enigmatic,
   exceptional, exclusive, extraordinary, fabulous, facile princeps,
   fantastic, fascinating, first and last, firsthand, fresh,
   idiocratic, idiosyncratic, imaginative, immortal, impair,
   in character, incomparable, incomprehensible, inconceivable,
   incredible, individual, indivisible, infrequent, inimitable,
   integral, intrinsic, invincible, irreducible, lone, marked,
   marvelous, matchless, miraculous, monadic, monistic, new,
   not that sort, not the same, not the type, novel, nulli secundus,
   odd, of a sort, of another sort, of sorts, offbeat, one,
   one and only, only, only-begotten, original, other, other than,
   otherwise, outlandish, particular, passing strange, peculiar,
   peerless, phenomenal, prodigious, proper, puzzling, quintessential,
   rare, recherche, remarkable, revolutionary, scarce, second to none,
   seldom met with, seldom seen, sensational, separate, simple,
   single, singular, slow, sole, solid, solitary, solo, sparse,
   special, strange, striking, stupendous, sui generis, true to form,
   unanalyzable, unapproachable, unapproached, unbeatable, uncommon,
   uncustomary, underived, undivided, undreamed-of, unequaled,
   unexampled, unexcelled, unexpected, unfamiliar, unfrequent,
   unheard-of, uniform, unimaginable, unitary, unmatchable, unmatched,
   unordinary, unpaired, unparagoned, unparalleled, unpeered,
   unprecedented, unrepeatable, unrepeated, unrivaled, unsurpassable,
   unsurpassed, unthinkable, unthought-of, unusual, unwonted, whole,
   without equal, without parallel, wonderful, wondrous