restraint of trade, an illegal act that interferes with free competition in a commercial or business transaction so as to restrict the production of a product or the provision of a service, affect the cost of a product or a service, or control the market in any way to the detriment of the consumers or purchasers of the service or product. The Clayton Act and the Sherman Antitrust Act are U.S. federal statutes that embody the basic concepts of the definition and the illegal nature of restraint of trade.
