idiosyncratic

from WordNet (r) 3.0 (2006)

idiosyncratic
    adj 1: peculiar to the individual; "we all have our own
           idiosyncratic gestures"; "Michelangelo's highly
           idiosyncratic style of painting"

from The Collaborative International Dictionary of English v.0.48

Idiosyncratic \Id`i*o*syn*crat"ic\, Idiosyncratical
\Id`i*o*syn*crat"ic*al\, a.
   Of peculiar temper or disposition; belonging to one's
   peculiar and individual character.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

102 Moby Thesaurus words for "idiosyncratic":
      abnormal, anomalous, appropriate, characteristic, characterizing,
      connotative, contrastive, crank, crankish, cranky, crotchety,
      demonstrative, denominative, denotative, designative, deviant,
      deviative, diacritical, diagnostic, differencing, different,
      differential, differentiative, discriminating, discriminative,
      distinctive, distinguished, distinguishing, divergent, dotty,
      eccentric, emblematic, erratic, evidential, exceptional,
      exhibitive, expressive, fey, figural, figurative, flaky, freakish,
      funny, identifying, ideographic, idiocratic, implicative,
      in character, indicating, indicative, indicatory, individual,
      individualizing, individuating, intrinsic, irregular, kinky, kooky,
      maggoty, marked, meaningful, metaphorical, naming, nutty, odd,
      oddball, pathognomonic, peculiar, personal, personalizing, private,
      proper, queer, quintessential, quirky, representative, screwball,
      screwy, semantic, semiotic, separative, signalizing, significant,
      significative, signifying, single, singular, strange, suggestive,
      symbolic, symbolistic, symbological, symptomatic, symptomatologic,
      true to form, twisted, typical, unconventional, unique, unnatural,
      wacky, whimsical