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]