conspiracy theory

American  

[kuhn-spir-uh-see theer-ee] / kənˈspɪr ə si ˌθɪər i /

noun

1. a theory that rejects the standard explanation for an event and instead credits a covert group or organization with carrying out a secret plot.

   One popular conspiracy theory accuses environmentalists of sabotage in last year's mine collapse.

2. a belief that a particular unexplained event was caused by such a covert group.

   A number of conspiracy theories have already emerged, purporting to explain last week's disappearance of a commercial flight over international waters.

3. the idea that many important political events or economic and social trends are the products of deceptive plots that are largely unknown to the general public.

   The more I learn about the activities of intelligence agencies, the less far-fetched I find many geopolitical conspiracy theories.

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conspiracy theory British  

noun

1. the belief that the government or a covert organization is responsible for an event that is unusual or unexplained, esp when any such involvement is denied

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Usage

What does conspiracy theory mean? A conspiracy theory is an explanation of an event that claims it was the result of a secret and often complex and evil plot by multiple people. Conspiracy theories and the conspiracy theorists who promote or formulate them often reject the standard or accepted explanation of unexplained or unusual events and claim that they are the doing of evil conspirators secretly conspiring behind the scenes. Conspiracy most commonly means a secret plan by multiple people to do something evil or illegal. Conspiracy can also refer to the act of making such plans—the act of conspiring—or to the group making the plans. The people involved can be called conspirators. In conspiracy theory, the word theory is used in a general way to refer to a proposed explanation that has not been proven. But conspiracy theorists don’t usually treat such theories as just guesses—they often promote them as fact, no matter how bizarre or far-fetched they may be. Most conspiracy theories involve supposedly secret knowledge of the supposedly secret and evil dealings of powerful people, especially politicians, government officials, billionaires, and celebrities. Such plots are often claimed to have the goal of controlling world events and ordinary people. Example: Why are several supposedly legitimate news outlets promoting conspiracy theories that have been repeatedly debunked?

Other Word Forms

• conspiracy theorist
  noun

Etymology

Origin of conspiracy theory

First recorded in 1905-10

Example Sentences

“Your average conspiracy theory, someone comes up with it and it dies on the vine,” said Joseph Uscinski, a professor at the University of Miami who studies them.

From The Wall Street Journal • Apr. 25, 2026

Kennedy was also a producer of “Medical Racism: The New Apartheid,” a 2021 conspiracy theory film from Children’s Health Defense, the anti-vaccine organization which Kennedy chaired, where he made over $20,000 a week.

From Salon • Apr. 21, 2026

The falsehoods -- circulating across tech platforms including X, TikTok and Facebook -- have also added fresh fuel to a longstanding conspiracy theory that NASA's 1969 Apollo 11 moon landing was faked.

From Barron's • Apr. 11, 2026

If every event is met with automatic suspicion and conspiracy theory, we’ll spend all our time debunking nonsense, and nothing will ever get better.

From Slate • Feb. 27, 2026

I almost thought he was going to rattle off some conspiracy theory, but Ms. Jacobs bailed him out.

From "Here to Stay" by Sara Farizan