unlawful activity

(1) any business enterprise involving gambling, liquor on which the Federal excise tax has not been paid, narcotics or controlled substances (as defined in section 102(6) of the Controlled Substances Act), or prostitution offenses in violation of the laws of the State in which they are committed or of the United States, or (2) extortion, bribery, or arson in violation of the laws of the State in which committed or of the United States.

Defined by the Supreme Court in Perrin v. United States, 444 U.S. 37 (1979).

See also 393 U.S. 410.