The Collaborative International Dictionary of English v.0.48:

gaiety \gai"e*ty\ (g[=a]"[-e]*t[y^]), n.
   Same as Gayety.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gayety \Gay"e*ty\, n.; pl. Gayeties. [Written also gaiety.]
   [F. gaiet['e]. See Gay, a.]
   1. The state of being gay; merriment; mirth; acts or
      entertainments prompted by, or inspiring, merry delight;
      -- used often in the plural; as, the gayeties of the
      season.
      [1913 Webster]

   2. Finery; show; as, the gayety of dress.

   Syn: Liveliness; mirth; animation; vivacity; glee;
        blithesomeness; sprightliness; jollity. See
        Liveliness.
        [1913 Webster]

WordNet (r) 3.0 (2006):

gaiety
    n 1: a gay feeling [syn: gaiety, merriment]
    2: a festive merry feeling [syn: gaiety, playfulness]

Moby Thesaurus II by Grady Ward, 1.0:

174 Moby Thesaurus words for "gaiety":
   Technicolor, animal spirits, animation, beatification, beatitude,
   bewitchment, blatancy, blessedness, bliss, blissfulness,
   blitheness, bravery, brazenness, bright color, brightness,
   brilliance, buoyancy, capersomeness, celebration, cheer,
   cheerfulness, cheeriness, chiffon, clinquant, cloud nine, color,
   colorfulness, coltishness, conviviality, crudeness, dash, dazzle,
   dazzlingness, delectation, delight, ecstasy, ecstatics, elan,
   elation, enchantment, entertainment, esprit, exaltation,
   exhilaration, extravagance, extravaganza, extravagation,
   exuberance, exultation, felicity, festivity, festoons, finery,
   flagrancy, flamboyance, flashiness, folderol, foofaraw, frilliness,
   frilling, frills, frills and furbelows, frippery, friskiness,
   frolicsomeness, froufrou, fuss, gamesomeness, garishness, gaudery,
   gaudiness, gayness, geniality, gilding, gilt, gingerbread,
   gladness, glare, glee, glitter, good cheer, good spirits,
   gorgeousness, gusto, happiness, heartiness, heaven, high spirits,
   hilarity, holiday-making, hoopla, intensity, intoxication,
   jauntiness, jazziness, joie de vivre, jollification, jollity,
   joviality, joy, joyance, joyfulness, joyousness, jubilation,
   larking, life, liveliness, loudness, luridness, mafficking,
   meretriciousness, merriment, merrymaking, mirth, mirthfulness,
   obtrusiveness, overhappiness, overjoyfulness, panache, paradise,
   paste, pinchbeck, piss and vinegar, playfulness, pleasantness,
   pleasure, pure color, racketing, radiance, rapture, ravishment,
   rejoicing, revel, reveling, revelment, revelry, revels, richness,
   rollicksomeness, rompishness, saturation, sensationalism,
   seventh heaven, shamelessness, showiness, skittishness, skylarking,
   spirit, spiritedness, spirits, sportiness, sportiveness,
   sprightliness, sunshine, superfluity, tawdriness, tinsel,
   transport, trappings, trickery, trumpery, unalloyed happiness,
   verve, vigor, vim, vitality, vivacity, vividness, vulgarness,
   whoopee, winsomeness, zest, zestfulness, zip