[ oh-ver-sel ]
/ ˌoʊ vərˈsɛl /

verb (used with object), o·ver·sold, o·ver·sell·ing.

to sell more of (a stock, product, etc.) than can be delivered.
to sell aggressively, as by using high-pressure merchandising techniques.
to emphasize the good points of excessively and to a self-defeating extent: She so oversold the picnic that I became convinced I'd have a better time at the movies.

verb (used without object), o·ver·sold, o·ver·sell·ing.

to sell something aggressively.
to make extreme claims for something or someone.

Origin of oversell

First recorded in 1570–80; over- + sell1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for oversell

/ (ˌəʊvəˈsɛl) /

verb -sells, -selling or -sold

(tr) to sell more of (a commodity) than can be supplied
to use excessively aggressive methods in selling (commodities)
(tr) to exaggerate the merits of
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012