The black economy consists of the buying, selling, and producing of goods or services that goes on without the government being informed, so that people can avoid paying tax on them. ( BRIT )
...an attempt to clamp down on the black economy.
N-SING
BLACK ECONOMY
Meaning of BLACK ECONOMY in English
Collins COBUILD Advanced Learner's English Dictionary. Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне. 2006