The Collaborative International Dictionary of English v.0.48:

Superfluity \Su`per*flu"i*ty\, n.; pl. Superfluities. [L.
   superfluit['e], L. superfluitas. See Superfluous.]
   1. A greater quantity than is wanted; superabundance; as, a
      superfluity of water; a superfluity of wealth.
      [1913 Webster]

            A quiet mediocrity is still to be preferred before a
            troubled superfluity.                 --Suckling.
      [1913 Webster]

   2. The state or quality of being superfluous; excess. "By a
      superfluity abominable." --Chaucer.
      [1913 Webster]

   3. Something beyond what is needed; something which serves
      for show or luxury.
      [1913 Webster]

   Syn: Superabundance; excess; redundancy.
        [1913 Webster]

WordNet (r) 3.0 (2006):

superfluity
    n 1: extreme excess; "an embarrassment of riches" [syn:
         overplus, plethora, superfluity, embarrassment]

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "superfluity":
   abundance, acres, amenity, amplitude, bags, barrels, bedizenment,
   bravery, bushel, chiffon, clinquant, cloud of words, copiousness,
   countlessness, diffuseness, diffusion, diffusiveness, duplication,
   duplication of effort, effusion, effusiveness, embellishment,
   excess, expletive, extravagance, exuberance, fat, featherbedding,
   fecundity, fertility, festoons, filling, finery, flood, fluency,
   folderol, foofaraw, formlessness, frill, frilliness, frilling,
   frills, frills and furbelows, frippery, froufrou, fuss, gaiety,
   gaudery, gilding, gilt, gingerbread, glut, gush, gushing, load,
   logorrhea, luxury, macrology, mass, mountain, much, multitude,
   needlessness, numerousness, ocean, oceans, ornamentation, outpour,
   overabundance, overadornment, overage, overflow, overflowing,
   overkill, overlap, overmuch, overplus, oversupply, padding,
   palilogy, paste, payroll padding, peck, pinchbeck, plenitude,
   plenty, pleonasm, plethora, prodigality, productivity, profuseness,
   profusion, prolificacy, prolificity, prolixity, quantities,
   quantity, rampancy, rankness, redundance, redundancy, reiteration,
   reiterativeness, repetition for effect, repetitiveness, sea, spate,
   superabundance, superfluousness, superflux, supersaturation,
   surfeit, surplus, surplusage, swarming, talkativeness, tautology,
   teeming, teemingness, tinsel, tirade, tons, trappings, trickery,
   trumpery, unnecessariness, verbosity, volume, world, worlds