The Collaborative International Dictionary of English v.0.48:

Profusion \Pro*fu"sion\, n. [L. profusio: cf. F. profusion.]
   [1913 Webster]
   1. The act of one who is profuse; a lavishing or pouring out
      without sting.
      [1913 Webster]

            Thy vast profusion to the factious nobles? --Rowe.
      [1913 Webster]

   2. Abundance; exuberant plenty; lavish supply; as, a
      profusion of commodities. --Addison.
      [1913 Webster]

WordNet (r) 3.0 (2006):

profusion
    n 1: the property of being extremely abundant; "the profusion of
         detail"; "the idiomatic richness of English" [syn:
         profusion, profuseness, richness, cornucopia]

Moby Thesaurus II by Grady Ward, 1.0:

158 Moby Thesaurus words for "profusion":
   abundance, accumulation, acres, affluence, agglomeration,
   ample sufficiency, ampleness, amplitude, avalanche, bags, barrels,
   bonanza, bountifulness, bountiousness, bounty, bumper crop, bushel,
   carpe diem, cloud of words, conglomeration,
   conspicuous consumption, copiousness, countlessness, diffuseness,
   diffusion, diffusiveness, dissipation, effusion, effusiveness,
   extravagance, exuberance, fecundity, fertility, flood, flow,
   fluency, foison, formlessness, full measure, fullness, generosity,
   generousness, glut, great abundance, great plenty, gush, gushing,
   heap, hoard, host, incontinence, infinitude, innumerability,
   intemperance, landslide, lavishness, leaking purse, liberality,
   liberalness, load, logorrhea, loose purse strings, lot, lots,
   luxuriance, macrology, manyness, mass, maximum, mess,
   more than enough, mountain, much, multifariousness, multifoldness,
   multiplicity, multitude, multitudinousness, myriad, myriads,
   nimiety, number, numerousness, ocean, oceans, opulence, opulency,
   outpour, outpouring, overflow, overgenerosity, overgenerousness,
   overliberality, oversupply, palilogy, peck, pile, plenitude,
   plenteousness, plentifulness, plenty, pleonasm, plethora,
   pound-foolishness, prevalence, prodigality, productiveness,
   productivity, profligacy, profuseness, prolificacy, prolificity,
   quantities, quantity, rampancy, rankness, reckless expenditure,
   reckless spending, redundancy, reiteration, reiterativeness,
   repetition for effect, repetitiveness, repleteness, repletion,
   rich harvest, rich vein, richness, rifeness, riot, riotousness,
   scads, sea, shower, spate, squandering, squandermania, stack,
   stream, substantiality, substantialness, superabundance,
   superfluity, superflux, surfeit, surplus, swarmingness,
   talkativeness, tautology, teemingness, tirade, tons, volume, waste,
   wastefulness, wealth, world, worlds