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
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
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 seamless pivot after a conspiracy theory implodes—no apology, no explanation, just on to the next conspiracy.
—Newsweek Editors, MSNBC Newsweek, 5 Dec. 2025
The timing of the pipe bombs and the January 6 riot has led to questions and conspiracy theories about whether they were connected in any way.
—Hannah Rabinowitz, CNN Money, 5 Dec. 2025
Andrew Harnik | Getty Images The timing of the pipe-bomb placement, and the elusiveness of the perpetrator, have made the case a hotbed of conspiracy theories.
—Kevin Breuninger, CNBC, 4 Dec. 2025
His murder remained unsolved for decades, fueling speculation and conspiracy theories in the hip-hop world.
—Samantha Stutsman, PEOPLE, 3 Dec. 2025
See All Example Sentences for conspiracy theory
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Newsweek Editors, MSNBC Newsweek, 5 Dec. 2025
The timing of the pipe bombs and the January 6 riot has led to questions and conspiracy theories about whether they were connected in any way.
—Hannah Rabinowitz, CNN Money, 5 Dec. 2025
Andrew Harnik | Getty Images The timing of the pipe-bomb placement, and the elusiveness of the perpetrator, have made the case a hotbed of conspiracy theories.
—Kevin Breuninger, CNBC, 4 Dec. 2025
His murder remained unsolved for decades, fueling speculation and conspiracy theories in the hip-hop world.
—Samantha Stutsman, PEOPLE, 3 Dec. 2025
See All Example Sentences for conspiracy theory
Cite this Entry
“Conspiracy theory.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/conspiracy%20theory. Accessed 12 Dec. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share