An oversupply is the state of having more of something than people need, or more than shops can sell. Farmers talk about an oversupply of fruit; the price often falls because so much is sitting there. Factories talk about an oversupply of chips or cars the same way. You can also use it as a verb: to oversupply a market. It is neat, slightly formal English from business and economics. In everyday talk, people say there's too much of it. Though actually, oversupply is about the amount out in the world — a market, a season, a country — not about one shop buying too much for its own shelves. That nearer word is overstock. The two sit side by side, and they are easy to mix.