conspiracy

noun

1.
a secret agreement between two or more people to perform an unlawful act
confederacy
Derived from:
conspiratorial conspire
2.
a plot to carry out some harmful or illegal act (especially a political plot)
plotlore cabal
Derived from:
conspire
3.
a group of conspirators banded together to achieve some harmful or illegal purpose
confederacy
Derived from:
conspiratorial