black money

noun

1. income earned surreptitiously or illegally, usually in cash, and not reported to the government so as to avoid paying taxes on it.

noun

1. that part of a nation’s income that relates to its black economy
2. any money that a person or organization acquires illegally, as by a means that involves tax evasion
3. US money to fund a government project that is concealed in the cost of some other project