Source : Webster's Revised Unabridged Dictionary (1913)

Overplus \O"ver*plus\, n. [Over + L. plus more. See {Plus}, and
   cf. {Surplus}.]
   That which remains after a supply, or beyond a quantity
   proposed; surplus. --Shak. ``The overplus of a great
   fortune.'' --Addison.

Source : WordNet®

overplus
     n : extreme excess; "an embarrassment of riches" [syn: {plethora},
          {superfluity}, {embarrassment}]