The Collaborative International Dictionary of English v.0.48:

Exorbitance \Ex*or"bi*tance\, Exorbitancy \Ex*or"bi*tan*cy\,, n.
   A going out of or beyond the usual or due limit; hence,
   enormity; extravagance; gross deviation from rule, right, or
   propriety; as, the exorbitances of the tongue or of
   deportment; exorbitance of demands. "A curb to your
   exorbitancies." --Dryden.
   [1913 Webster]

         The lamentable exorbitances of their superstitions.
                                                  --Bp. Hall.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exorbitance
    n 1: excessive excess [syn: exorbitance, outrageousness]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "exorbitance":
   abandon, aggrandizement, amplification, ballyhoo, big talk,
   blowing up, boundlessness, burlesque, caricature, dilatation,
   dilation, egregiousness, enhancement, enlargement, enormousness,
   exaggerating, exaggeration, excess, excessiveness, exorbitancy,
   expansion, extortionateness, extravagance, extravagancy, extreme,
   extremes, extremism, extremity, fabulousness, giantism, gigantism,
   gluttony, grandiloquence, heightening, huckstering, hyperbole,
   hyperbolism, hypertrophy, immoderacy, immoderateness, immoderation,
   incontinence, inflation, inordinacy, inordinance, inordinateness,
   intemperance, intemperateness, magnification, monstrousness,
   nimiety, outrageousness, overdevelopment, overemphasis,
   overestimation, overgreatness, overgrowth, overindulgence,
   overkill, overlargeness, overmuch, overmuchness, overstatement,
   preposterousness, prodigality, profuseness, puffery, puffing up,
   radicalism, sensationalism, stretching, superlative, tall talk,
   too much, too-muchness, touting, travesty, unconscionableness,
   undueness, unreasonableness, unrestrainedness