The Collaborative International Dictionary of English v.0.48:

Dilettante \Dil`et*tan"te\, n.; pl. Dilettanti. [It., prop. p.
   pr. of dillettare to take delight in, fr. L. delectare to
   delight. See Delight, v. t.]
   An admirer or lover of the fine arts; popularly, an amateur;
   especially, one who follows an art or a branch of knowledge,
   desultorily, or for amusement only.
   [1913 Webster]

         The true poet is not an eccentric creature, not a mere
         artist living only for art, not a dreamer or a
         dilettante, sipping the nectar of existence, while he
         keeps aloof from its deeper interests.   --J. C.
                                                  Shairp.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dilettante
    adj 1: showing frivolous or superficial interest; amateurish;
           "his dilettantish efforts at painting" [syn:
           dilettante, dilettantish, dilettanteish,
           sciolistic]
    n 1: an amateur who engages in an activity without serious
         intentions and who pretends to have knowledge [syn:
         dabbler, dilettante, sciolist]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "dilettante":
   Sunday painter, abecedarian, admirer, aesthete, aficionado,
   amateur, arbiter, arbiter elegantiarum, arbiter of taste,
   authority, bon vivant, booster, buff, cognoscente, collector,
   connaisseur, connoisseur, coquet, critic, criticaster, dabbler,
   dabbling, dabster, dallier, devotee, dilettantish, dunce, epicure,
   epicurean, expert, fan, fancier, flirt, follower, fool, freak,
   fribble, good judge, gourmand, gourmet, grammaticaster, greenhorn,
   greeny, groupie, half scholar, idolater, idolizer, ignoramus,
   illiterate, illiterati, jackleg, judge, know-nothing, lowbrow,
   maven, middlebrow, no scholar, nonprofessional, nut, philologaster,
   philosophaster, piddler, potterer, puddinghead, pundit, putterer,
   refined palate, rooter, savant, scholar, sciolist, smatterer,
   specialist, technical expert, technician, tenderfoot, trifler,
   tyro, unaccomplished, unfinished, ungifted, unintelligentsia,
   unskilled, virtuoso, votary, worshiper