Spoofing is a way of manipulating markets by placing fake orders to buy or sell assets, like stocks, commodities, and cryptocurrencies. Typically, traders who attempt to spoof the market use bots or algorithms to automatically place orders to buy or sell. When the orders get close to getting filled, the bots cancel the orders.
The main idea behind spoofing is trying to create a false impression of buy or sell pressure. For example, a spoofer may set a large number of fake buy orders to create a false sense of demand at a price level. Then, as the market gets close to the level, they pull the orders, and the price continues to the downside.