Forestaller is a term used to refer to a person who engages in the practice of undercutting legitimate trade by purchasing goods with the intention of selling them for a higher price. This practice was common in medieval times, where forestallers would often gather goods such as grain, meat, and fish and then sell them for a higher price, causing hardship for the poor. Synonyms for forestaller include profiteer, hoarder, speculator, opportunist, and middleman. These terms all describe individuals who seek to profit at the expense of others by manipulating the market, often by creating a shortage of goods and driving up prices. Such practices have been the subject of scrutiny for centuries and are still frowned upon in modern times.