Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun, con·spir·a·cy \kən-ˈspir-ə-sē\

Simple Definition of conspiracy

  • : a secret plan made by two or more people to do something that is harmful or illegal

  • : the act of secretly planning to do something that is harmful or illegal

Source: Merriam-Webster's Learner's Dictionary

Full Definition of conspiracy

plural conspiracies

  1. 1 :  the act of conspiring together

  2. 2 a :  an agreement among conspirators b :  a group of conspirators

Examples of conspiracy in a sentence

  1. The CIA uncovered a conspiracy against the government.

  2. They were accused of conspiracy to commit murder.

Origin of conspiracy

Middle English conspiracie, from Latin conspirare

First Known Use: 14th century

Synonym Discussion of conspiracy

plot, intrigue, machination, conspiracy, cabal mean a plan secretly devised to accomplish an evil or treacherous end. plot implies careful foresight in planning a complex scheme <an assassination plot>. intrigue suggests secret underhanded maneuvering in an atmosphere of duplicity <backstairs intrigue>. machination implies a contriving of annoyances, injuries, or evils by indirect means <the machinations of a party boss>. conspiracy implies a secret agreement among several people usually involving treason or great treachery <a conspiracy to fix prices>. cabal typically applies to political intrigue involving persons of some eminence <a cabal among powerful senators>.

CONSPIRACY Defined for Kids


noun con·spir·a·cy \kən-ˈspir-ə-sē\

Definition of conspiracy for Students

plural conspiracies

  1. 1 :  a secret agreement to do something harmful or unlawful

  2. 2 :  the act of plotting with others to do something harmful or unlawful

  3. 3 :  a group of conspirators

Law Dictionary


noun con·spir·a·cy \kən-ˈspir-ə-sē\

Legal Definition of conspiracy

plural conspiracies

  1. 1 :  an agreement between two or more people to commit an act prohibited by law or to commit a lawful act by means prohibited by law; also :  the crime or tort of participating in a conspiracy — compare substantive crime Editor's note: Some states require an overt act in addition to the agreement to constitute conspiracy. chain conspiracy :  a conspiracy in which the conspirators act separately and successively (as in distributing narcotics) civil conspiracy :  a conspiracy that is not prosecuted as a crime but that forms the grounds for a lawsuit criminal conspiracy :  a conspiracy prosecuted as a crime

  2. 2 :  a group of conspirators

Origin of conspiracy

Latin conspiratio, from conspirare to conspire — see conspire

Seen and Heard

What made you want to look up conspiracy? Please tell us where you read or heard it (including the quote, if possible).


to manage or play awkwardly

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which of these is a synonym of nonplus?

disapprove reduce soothe perplex
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.