conspiracy theory

• (Received Pronunciation) IPA^(key): /kənˈspɪɹəsi θɪəɹi/, /- θiːəɹi/
• (General American) IPA^(key): /kənˈspɪɹəsi θi.əɹi/, /- θɪɹi/
• (General Australian) IPA^(key): /kənˈspɪɹəsiː θɪəɹiː/, /- θiːəɹiː/
• (General New Zealand) IPA^(key): /kɘnˈspɘɹɘsiː θiəɹiː/, /- θiːɘɹiː/

conspiracy theory (plural conspiracy theories)

1. A hypothesis alleging that the members of a coordinated group are, and/or were, secretly working together to commit illegal or wrongful actions including attempting to hide the existence of the group and its activities. In notable cases the hypothesis contradicts the mainstream explanation for historical or current events. [1960s]
   • 2007, Charles R. Pigden, “Conspiracy Theories and the Conventional Wisdom”, in Episteme: A Journal of Social Epistemology, volume 4, number 2, Edinburgh University Press, DOI:10.1353/epi.2007.0017, page 222:

     (A) conspiracy theory is simply a theory that posits a conspiracy – a secret plan on the part of some group to influence events by partly secret means.

   • 2018 September 12, Abby Ohlheiser, “Reddit bans r/greatawakening, the main subreddit for QAnon conspiracy theorists”, in The Washington Post‎:

     QAnon, whose supporters also call it “The Storm" or “Great Awakening,” is a wide-ranging conspiracy theory that burst into greater visibility this summer, after supporters at a Trump rally wearing Q shirts prompted a rush of national media coverage about it.

2. (dismissive, derogatory) Hypothetical speculation that is commonly considered untrue or outlandish.
   • 2007, Rick Huffman, Baxter Peanut, Xlibris Corporation, →ISBN, page 153:

     “So, like I’m Rock Hudson? I’m not sure that’s the answer.”
     “Ah,” Lola smiles knowingly, “that’s all just a conspiracy theory. He enjoyed the ladies too.”

• The phrase conspiracy theory is sometimes used in an attempt to imply that hypothetical speculation is not worthy of serious consideration, usually with phrasing indicative of dismissal (e.g., "just a conspiracy theory"). However, any particular instance of use is not necessarily pejorative. Some consider it inappropriate to use the phrase "conspiracy theory" in an attempt to dismissively discredit hypothetical speculation in any form.

• conspiracy theorist