/ ˌəʊvəˈsel; NAmE ˌoʊvərˈsel/ verb ( over·sold , over·sold / ˌəʊvəˈsəʊld; NAmE ˌoʊvərˈsoʊld/) [ vn ] [ often passive ]
1.
to say that sb/sth is better than they really are :
He has a tendency to oversell himself.
2.
( business ) to sell too much or more of sth than is available :
The seats on the plane were oversold.