What kind of profession were Bootleggers involved with?

Bootlegging, in U.S. history, illegal traffic in liquor in violation of legislative restrictions on its manufacture, sale, or transportation. The word apparently came into general use in the Midwest in the 1880s to denote the practice of concealing flasks of illicit liquor in boot tops when going to trade with Native Americans. The term entered into the wider American vocabulary when the Eighteenth Amendment to the U.S. Constitution effected the national prohibition of alcohol from 1920 until its repeal in 1933.