conspiracy, n.
a. The action of conspiring; combination of persons for an evil or unlawful purpose.
c1386—1841(Hide quotations)
b. Law.
1863—1863(Hide quotations)
a. (with a and plural) A combination of persons for an evil or unlawful purpose; an agreement between two or more persons to do something criminal, illegal, or reprehensible (especially in relation to treason, sedition, or murder); a plot. Also in conspiracy of silence.
c1386—1965(Hide quotations)
†b. A body or band of conspirators. Obsolete.
1555—1600(Hide quotations)
3. figurative. Union or combination (of persons or things) for one end or purpose; harmonious action or effort; = conspiration n. 3 (In a good or neutral sense.) Obsolete or archaic.
a1538—1847(Hide quotations)
Draft additions 1997
conspiracy theory n. the theory that an event or phenomenon occurs as a result of a conspiracy between interested parties; spec. a belief that some covert but influential agency (typically political in motivation and oppressive in intent) is responsible for an unexplained event.
1909—1987(Hide quotations)
conspiracy theorist n.
1964—1990(Hide quotations)