An agreement or arrangement between multiple parties to do something harmful, immoral or subversive; an instance of collusion.
Conspiracies, like all other exercises of human ingenuity, are of very different kinds. The gloomy plots arranged in old Italian halls...1834, L[etitia] E[lizabeth] L[andon], chapter IV, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC, page 23:
And you may have noticed that those who are too quick to shout 'conspiracy theorist' are equally swift, when consequences for authority and consensus impend, to look serious and say 'It's more complicated than that.' These have become standard damage-control reflexes.1993, Christopher Hitchens, For the Sake of Argument:
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Modern political religions may reject Christianity, but they cannot do without demonology. The Jacobins, the Bolsheviks and the Nazis all believed in vast conspiracies against them, as do radical Islamists today. It is never the flaws of human nature that stand in the way of Utopia. It is the workings of evil forces.2007, John Gray, Apocalyptic Religion and the Death of Utopia:
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Law An agreement between two or more persons to break the law at some time in the future.
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Broadly A secret agreement to do something.
The former programme of the entertainments, which were to result from this generous conspiracy to assist a man whom fortune had buffeted, was eagerly looked for, not only for the reunion of old favorites that it promised to bring about, but out of sympathy for the sentiment which has prompted this graceful act of kindness.1863 May 30, “Lord Dudley and Mr. Lumley”, in The Musical World, volume 41, number 22, page 339:
On another occasion, some months later, when Currita's birthday, the 10th of October, and feast of St. Francis Borgia, was approaching, the two children were plotting together a conspiracy to give their mother a surprise.1900, Luis Coloma, Currita, Countess of Albornoz, page 245:
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The people whom he visited were members of the surprise party conspiracy, and kept the pianist involved in a heated discussion until they were sure that the surprise was ready for him.1916 August 10, “Ernest schelling Given A Surprise Party”, in Musical Courier and Review of Recorded Music, volume 73, page 27:
When Mike and his family showed up at nearly the same time, Dan suspected a conspiracy among his mother, brother and sister. He was not surprised to learn that his mother had concocted the plan to get the whole family together again.2002, Duane Ramsey, Reunion in the Rockies, page 264:
Have you been part of a surprise party conspiracy or plotted a delightful treat for someone you love?2003, Penelope S. Tzougros, Wealthy Choices: The Seven Competencies of Financial Success, page 234:
[…2004 December 7, Thomas Kinkade, A New Leaf: A Cape Light Novel, Penguin, →ISBN, page 252:
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Broadly An agreement to work together to bring something about; an act or instance of conspiring.
But this I call civil life […] living [together] in good and politic order, one ever ready to do good to another, and as it were conspiring [together] in all virtue and honesty. […] You said right now that this civil life was a politic order and, as it were, a conspiracy in honesty and virtue, […]1948 [c. 1530], Thomas Starkey, A Dialogue Between Reginald Pole & Thomas Lupset:
You may even find yourself using your new awareness and insight to assist others in their recovery process. A conspiracy to enable others joins the minds of all who seek faces of recovery.2007, Barbara Sinor, Gifts from the Child Within, page 188:
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By teaming up, local educators and community leaders can forge a potent, positive conspiracy to help our children to strive for success in school and ultimately in life.2010 June 21, Hugh B. Price, Mobilizing the Community to Help Students Succeed, ASCD, →ISBN, page 128:
When collaboration is conscious, planned, and shared with others, excitement builds and a conspiracy develops.2013, Leigh Thompson, Creative Conspiracy: The New Rules of Breakthrough Collaboration, page 1:
Retelling stories can provide a time of reflection, but the idea is to create a conspiracy to open up new ways of thinking in order to change education.2021, Dana Compton McCullough, Mandy Hoffen and a Conspiracy to Resurrect Life and Social Justice in Science Curriculum With Henrietta Lacks:
Indeed, as I sat, forlorn, never having found my particular conspiracy of lemurs (how about that for a name for a group of lemurs? The name lemur itself comes from the Latin for “spirits of the dead”) …2018 February 8, Jeffrey T. Laitman, “The Search for the Intersection of Form and Function: Looking for Clues into What Has Determined How, Why, and When Animals Came to Move the Way They Do”, in The Anatomical Record, volume 301, number 3, →DOI:
The Oregon Zoo welcomed two red-ruffed lemurs this week, bringing the total number in the conspiracy — the name for a group of lemurs — to seven.2018 November 9, “Red alert: New lemurs join zoo conspiracy”, in Oregon Zoo, archived from the original on 31 Aug 2025, retrieved 05 Nov 2019:
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Human sciences, Linguistics, Sciences A situation in which different phonological or grammatical rules lead to similar or related outcomes.
That is, further exploration of phonological systems of various languages may turn up evidence motivating conspiracies that have been regarded thus far as impossible.[…]This study of labial palatalization conspiracy is a contribution to the 'too many solutions'/'too few data' problem.2014, Jerzy Rubach, “Soft labial conspiracy in Kurpian”, in Journal of Linguistics, volume 50, number 1:
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Proscribed A conspiracy theory; a hypothesis alleging conspiracy.
Rather than propagating conspiracies about the evils of wealthy Jewry, they beat up poor Roma in back alleys.2008, Edward Snajdr, Nature Protests: The End of Ecology in Slovakia, University of Washington Press, →ISBN, page 176:
The internet helps spread conspiracies, but it can also be used to verify claims made by politicians and the media.2018, Rita Santos, The Deep State, Greenhaven Publishing, →ISBN, page 99:
He knew I would come for him when I discovered what he did, so he, he conspiracied to put me in prison.2007, Brian Francis Slattery, Spaceman Blues: A Love Song, page 45:
“What are you two conspiracying about up here?” asked Kira, walking up next to me.2019, Vincent Trigili, Rise of the Goblin King:
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Promoters of the CrowdStrike theory often claim that CrowdStrike co-founder Dmitri Alperovitch is Ukrainian, which they see as “proof” of his willingness to conspiracy with the Ukrainian government and Democrats against Putin and Trump in 2016.2019 November 21, Alex Henderson, “The looney CrowdStrike conspiracy claims debunked by Fiona Hill during her bombshell impeachment testimony”, in AlterNet: