the act of conspiring.

an evil, unlawful, treacherous, or surreptitious plan formulated in secret by two or more persons; plot.

a combination of persons for a secret, unlawful, or evil purpose

He joined the conspiracy to overthrow the government.

Law . an agreement by two or more persons to commit a crime, fraud, or other wrongful act.

any concurrence in action; combination in bringing about a given result.

noun

cabal , complot , confederacy , connivance , countermine , counterplot , covin , disloyalty , fix , frame * , game , hookup , intrigue , league , little game , machination , perfidy , plot , practice , put-up job , scheme , sedition , treacherousness , treachery , treason , trick , trickery , collusion , agreement , coup , plan