Synonyms 1. collusion, sedition. 2. Conspiracy, plot, intrigue, cabal all refer to surreptitious or covert schemes to accomplish some end, most often an evil one. A conspiracy usually involves a group entering into a secret agreement to achieve some illicit or harmful objective: a vicious conspiracy to control prices. A plot is a carefully planned secret scheme, usually by a small number of persons, to secure sinister ends: a plot to seize control of a company. An intrigue usually involves duplicity and deceit aimed at achieving either personal advantage or criminal or treasonous objectives: the petty intrigues of civil servants.Cabal refers either to a plan by a small group of highly-placed persons to overthrow or control a government, or to the group of persons themselves: a cabal of powerful lawmakers.
late 14c., from L. conspiratio, noun of action from conspirare (see conspire); earlier conspiration (c.1300), from Fr. conspiration (13c.), from L. conspirationem, acc. of conspiratio. As a term in law, from 1863. Conspiracy theory is from 1909.