oversello·ver·sell /ˌəʊvəˈselˌoʊvər-/ (also over-sell) verb (past tensepst and past participlepp oversold /-ˈsəʊld-ˈsoʊld/) [transitiveT]1MARKETINGto say that something you are selling is better, more useful etc than it really isVendors tend to oversell the software. That gives people more confidence to work with it than they should have.
2COMMERCEto sell more of something than is availableThey regularly oversold seats on their flights.
—overselling noun [uncountableU]He’s investigating the possible overselling of time-share resorts.