The Collaborative International Dictionary of English v.0.48:

Distinctive \Dis*tinc"tive\, a. [Cf. F. distinctif.]
   1. Marking or expressing distinction or difference;
      distinguishing; characteristic; peculiar.
      [1913 Webster]

            The distinctive character and institutions of New
            England.                              --Bancroft.
      [1913 Webster]

   2. Having the power to distinguish and discern;
      discriminating. [Obs.] --Sir T. Browne.
      [1913 Webster]

WordNet (r) 3.0 (2006):

distinctive
    adj 1: of a feature that helps to distinguish a person or thing;
           "Jerusalem has a distinctive Middle East flavor"- Curtis
           Wilkie; "that is typical of you!" [syn: distinctive,
           typical]
    2: capable of being classified [syn: classifiable,
       distinctive]

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "distinctive":
   accurate, appreciative, appropriate, articulate, audible,
   categorical, characteristic, characterizing, classificational,
   classificatory, clear, contrastive, critical, defining, definite,
   delicate, denominative, diacritical, diagnostic, differencing,
   differential, differentiative, discrete, discriminate,
   discriminating, discriminative, distinct, distinguished,
   distinguishing, divisional, divisionary, exact, exemplary,
   fastidious, fine, hearable, hi-fi, high-fidelity, idiocratic,
   idiosyncratic, in character, individual, individualizing,
   individuating, intrinsic, marked, natural, naturalistic, nice,
   normal, ordinal, particular, peculiar, personalizing, plain,
   precise, proper, quintessential, realistic, refined, regular,
   sample, selective, sensitive, separate, separative, several,
   single, singular, special, specific, subdivisional, subtle,
   tactful, taxonomic, true to form, true to type, typal, typic,
   typical, unique, usual