The phrase "black marketeers" refers to people who are involved in illegal buying and selling of goods or services outside the control of the government. They operate in secret, often evading taxes and regulations. Full definition
Because the digital currency abjured central banks and other authorities, many of its first devotees were libertarians, anarchists, and black marketeers who wanted to do business away from the government's watchful eye. (fortune.com)
Trevor Howard, most famous for much more civilized turns in films like «Brief Encounter» and «The Third Man,» delivers one of his most dynamic performances as an ex-serviceman who, bored with civilian life, joins a gang of black marketeers for excitement and money. (seanax.com)