The Collaborative International Dictionary of English v.0.48:

Excess \Ex*cess"\, n. [OE. exces, excess, ecstasy, L. excessus a
   going out, loss of self-possession, fr. excedere, excessum,
   to go out, go beyond: cf. F. exc[`e]s. See Exceed.]
   1. The state of surpassing or going beyond limits; the being
      of a measure beyond sufficiency, necessity, or duty; that
      which exceeds what is usual or proper; immoderateness;
      superfluity; superabundance; extravagance; as, an excess
      of provisions or of light.
      [1913 Webster]

            To gild refined gold, to paint the lily,
            To throw a perfume on the violet, . . .
            Is wasteful and ridiculous excess.    --Shak.
      [1913 Webster]

            That kills me with excess of grief, this with excess
            of joy.                               --Walsh.
      [1913 Webster]

   2. An undue indulgence of the appetite; transgression of
      proper moderation in natural gratifications; intemperance;
      dissipation.
      [1913 Webster]

            Be not drunk with wine, wherein is excess. --Eph. v.
                                                  18.
      [1913 Webster]

            Thy desire . . . leads to no excess
            That reaches blame.                   --Milton.
      [1913 Webster]

   3. The degree or amount by which one thing or number exceeds
      another; remainder; as, the difference between two numbers
      is the excess of one over the other.
      [1913 Webster]

   Spherical excess (Geom.), the amount by which the sum of
      the three angles of a spherical triangle exceeds two right
      angles. The spherical excess is proportional to the area
      of the triangle.
      [1913 Webster]

WordNet (r) 3.0 (2006):

excess
    adj 1: more than is needed, desired, or required; "trying to
           lose excess weight"; "found some extra change lying on
           the dresser"; "yet another book on heraldry might be
           thought redundant"; "skills made redundant by
           technological advance"; "sleeping in the spare room";
           "supernumerary ornamentation"; "it was supererogatory of
           her to gloat"; "delete superfluous (or unnecessary)
           words"; "extra ribs as well as other supernumerary
           internal parts"; "surplus cheese distributed to the
           needy" [syn: excess, extra, redundant, spare,
           supererogatory, superfluous, supernumerary,
           surplus]
    n 1: a quantity much larger than is needed [syn: excess,
         surplus, surplusage, nimiety]
    2: immoderation as a consequence of going beyond sufficient or
       permitted limits [syn: excess, excessiveness,
       inordinateness]
    3: the state of being more than full [syn: surfeit, excess,
       overabundance]
    4: excessive indulgence; "the child was spoiled by
       overindulgence" [syn: overindulgence, excess]

Moby Thesaurus II by Grady Ward, 1.0:

149 Moby Thesaurus words for "excess":
   Saturnalia, aggrandizement, amplification, ballyhoo, big talk,
   blowing up, burlesque, caricature, crapulence, crapulency,
   crapulousness, de trop, debauchery, dilatation, dilation,
   disentitlement, dispensable, dissipation, dissoluteness,
   drunkenness, empty claim, empty title, enhancement, enlargement,
   exaggerating, exaggeration, excessive, excessiveness, exorbitance,
   exorbitancy, expansion, expendable, expletive, extortionateness,
   extra, extravagance, extreme, false claim, fat, glut, gluttony,
   grandiloquence, gratuitous, heightening, huckstering, hyperbole,
   hyperbolism, immoderacy, immoderateness, immoderation, impropriety,
   in excess, inappropriateness, incontinence, indiscipline,
   indulgence, inflation, inordinacy, inordinateness, intemperance,
   intemperateness, inundation, invalid claim, lack of claim,
   leftover, leftovers, magnification, needless, nimiety, no claim,
   nonessential, outrageousness, overabundance, overage, overbalance,
   overdoing, overemphasis, overestimation, overflow, overflowing,
   overgrowth, overindulgence, overkill, overmeasure, overmuch,
   overpass, overplus, overproduction, overrun, overrunning,
   overspill, overspreading, overstatement, overstock, oversupply,
   pleonastic, plethora, plus, preposterousness, prodigality,
   profuseness, profusion, prolix, puffery, puffing up, redundancy,
   redundant, remaining, residual, self-indulgence, self-restraint,
   sensationalism, spare, stretching, superabundance, supererogation,
   supererogatory, superfluity, superfluous, superiority, superlative,
   supernumerary, surfeit, surplus, surplusage, swinishness,
   tall talk, tautologic, tautologous, to spare, too much,
   too-muchness, touting, travesty, uncalled-for, unconscionableness,
   unconstraint, uncontrol, undeservedness, undeservingness,
   undueness, unentitledness, unessential, unmeritedness, unnecessary,
   unneeded, unreasonableness, unrestraint, verbose



The Devil's Dictionary (1881-1906):

EXCESS, n.  In morals, an indulgence that enforces by appropriate
penalties the law of moderation.

    Hail, high Excess -- especially in wine,
        To thee in worship do I bend the knee
        Who preach abstemiousness unto me --
    My skull thy pulpit, as my paunch thy shrine.
    Precept on precept, aye, and line on line,
        Could ne'er persuade so sweetly to agree
        With reason as thy touch, exact and free,
    Upon my forehead and along my spine.
    At thy command eschewing pleasure's cup,
        With the hot grape I warm no more my wit;
        When on thy stool of penitence I sit
    I'm quite converted, for I can't get up.
    Ungrateful he who afterward would falter
    To make new sacrifices at thine altar!