conspiracy theory

plural conspiracy theories

Definition of conspiracy theory

: a theory that explains an event or set of circumstances as the result of a secret plot by usually powerful conspirators the conspiracy theories surrounding Kennedy's assassination also : a theory asserting that a secret of great importance is being kept from the public … is best known for … his conspiracy theory that a secret cabal of reptilian humanoids is running the world. — Simon Little … has often been criticized for promoting conspiracy theories such as "birtherism," the theory that President Obama was not born in the U.S. — Grace Segers

Examples of conspiracy theory in a Sentence

Conspiracy theories sprung up soon after the leader's assassination.
Recent Examples on the Web The idea, then, that the election was stolen is a wild conspiracy theory. Chris Cillizza, CNN, 13 Sep. 2021 The controversy that threatened to derail the show was a definitely sincere conspiracy theory that actor Brett Goldstein (Roy Kent) is in fact a robot. Jacob Siegal, BGR, 28 Aug. 2021 That is either an AWFUL lot of time and effort to put in, or it’s a patently absurd conspiracy theory on its face. Robert Gehrke, The Salt Lake Tribune, 27 July 2021 Claims have falsely alleged that the recount uncovered tens of thousands of fraudulent votes and that auditors found watermarked ballots, which is a conspiracy theory with ties to the far-right QAnon. Jeanine Santucci, USA TODAY, 18 May 2021 ABC News previously reported on the Department's concern about the conspiracy theory that former President Donald Trump will be reinstated as U.S. president last Friday. Luke Barr, ABC News, 14 Aug. 2021 The allure of systems of the kind this gigging Gordon Gekko threw away his money on is fundamentally the same as the allure of conspiracy theories and conspiracy theory-adjacent political beliefs: secret knowledge. Kevin D. Williamson, National Review, 29 Apr. 2021 Just because crappy people exist in real life doesn't mean that the cast has to contain crappy people (cough — conspiracy theory-spouting alumni). Dalton Ross,, 10 Mar. 2021 Inauguration Day was supposed to be a climactic moment for believers of QAnon, the conspiracy theory that claims Donald Trump is leading a clandestine campaign against cannibalistic, deep state–dwelling pedophiles. Jacob Silverman, The New Republic, 20 Jan. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'conspiracy theory.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of conspiracy theory

1863, in the meaning defined above

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Time Traveler for conspiracy theory

Time Traveler

The first known use of conspiracy theory was in 1863

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Dictionary Entries Near conspiracy theory

conspiracy theorist

conspiracy theory


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Statistics for conspiracy theory

Last Updated

25 Sep 2021

Cite this Entry

“Conspiracy theory.” Dictionary, Merriam-Webster, Accessed 28 Sep. 2021.

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More Definitions for conspiracy theory

conspiracy theory


English Language Learners Definition of conspiracy theory

: a theory that explains an event or situation as the result of a secret plan by usually powerful people or groups


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