The Collaborative International Dictionary of English v.0.48:

jazzy \jazzy\ adj.
   1. resembling jazz[1] especially in its rhythm. [WordNet
      sense 1]
      [WordNet 1.5]

   2. ostentatious or strikingly styled; -- used especially of
      clothes. [WordNet sense 2]

   Syn: flashy, gaudy, showy, snazzy, sporty.
        [WordNet 1.5]

   3. marked by animation or performed with flair[2].
      [PJC]

WordNet (r) 3.0 (2006):

jazzy
    adj 1: resembling jazz (especially in its rhythm)
    2: (used especially of clothes) marked by conspicuous display
       [syn: flashy, gaudy, jazzy, showy, sporty]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "jazzy":
   brave, bravura, braw, chichi, concert, daring, dashing,
   dramatico-musical, dressy, exhibitionistic, flashing, flashy,
   flaunting, frilly, frothy, gallant, gay, glittering, hot,
   instrumental, jaunty, jazz, jazzed up, orchestral, ragtime,
   ragtimey, rakish, rock, showy, snazzy, splashy, splurgy, sporty,
   swing, swingy, symphonic, syncopated