idiosyncratic

adj. characteristic of, peculiar to; eccentric

Idiosyncrasy comes from Greek ιδιοσυγκρασία "a peculiar temperament", "habit of body" (idios "one's own" and sun-krasis "mixture"). It is defined as a structural or behavioral characteristic peculiar to an individual or group. The term can also be applied to symbols. Idiosyncratic symbols mean one thing for a particular person, as a blade could mean war, but to someone else, it could symbolize a knighting. By the same principle, linguists state that words are not only arbitrary, but also largely idiosyncratic signs.
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Adjective
1. peculiar to the individual; "we all have our own idiosyncratic gestures"; "Michelangelo's highly idiosyncratic style of painting"
(similar) individual

(a.)
Alt. of Idiosyncratical
  

Synonyms and related words:
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