The Collaborative International Dictionary of English v.0.48:

Oversupply \O"ver*sup*ply`\, n.
   An excessive supply; a supply in excess of demand.
   [1913 Webster]

         A general oversupply or excess of all commodities. --J.
                                                  S. Mill.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Oversupply \O`ver*sup*ply"\, v. t.
   To supply in excess.
   [1913 Webster]

WordNet (r) 3.0 (2006):

oversupply
    n 1: the quality of being so overabundant that prices fall [syn:
         glut, oversupply, surfeit]
    v 1: supply with an excess of; "flood the market with tennis
         shoes"; "Glut the country with cheap imports from the
         Orient" [syn: flood, oversupply, glut]

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "oversupply":
   avalanche, balance, be prodigal with, bonus, deluge, dividend,
   embarras de richesses, engulf, enough, extra, extravagance,
   extravagancy, flood, flood the market, gratuity, inundate,
   inundation, lagniappe, landslide, lavishness, leftover, margin,
   money to burn, more than enough, overabundance, overaccumulation,
   overage, overbounteousness, overcopiousness, overdose, overequip,
   overfurnish, overlavish, overlavishness, overluxuriance,
   overmeasure, overmuchness, overnumerousness, overplentifulness,
   overplenty, overplus, overpopulation, overprofusion, overprovender,
   overprovide, overprovision, overrun, oversell, overset, overstock,
   oversufficiency, overwhelm, plenty, plethora, plus, pourboire,
   prodigality, redundancy, remainder, something extra, spare, spate,
   superabundance, superflux, surplus, surplusage, swamp, tip,
   whelm