conspiracy theory

noun

plural conspiracy theories

: 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

When 38-year-old Robert Rauschenberg was named grand prize winner at the esteemed art festival, a furor erupted — and the conspiracy theories took flight. —Jessica Gelt, Los Angeles Times, 25 May 2024

State Farm Arena quickly became the subject of conspiracy theories about illicit votes spread by Trump and his associates on social media in the hours following the election. —Sudiksha Kochi, USA TODAY, 21 May 2024

But Slovakia’s politics are particularly poisonous, swamped by wild conspiracy theories and bile. —Andrew Higgins, New York Times, 19 May 2024

Giuliani filed for bankruptcy after being ordered to pay $148 million to two former election workers for spreading a false conspiracy theory about their role in the 2020 election. —CBS News, 18 May 2024

Word History

First Known Use

1863, in the meaning defined above

Kids Definition

conspiracy theory

noun

: a theory that explains an event or situation as being the result of a secret plot

conspiracy theorist noun