Definitions for oversellˌoʊ vərˈsɛl
Random House Webster's College Dictionary
o•ver•sellˌoʊ vərˈsɛl(v.t.)-sold, -sell•ing.
to sell more of than can be delivered.
to sell too aggressively to.
to emphasize the good points of excessively; praise too highly.
Origin of oversell:
To agree to sell more of something than one can supply.
To be too eager in attempting to sell something.
To praise something to excess.