conjecture
Americannoun
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conjectures
plural
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the formation or expression of an opinion or theory without sufficient evidence for proof.
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an opinion or theory so formed or expressed; guess; speculation.
- Synonyms:
- hypothesis, theory, supposition, inference, surmise
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Obsolete. the interpretation of signs or omens.
verb (used with object)
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conjectures,
present (3rd person singular)
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conjectured,
past participle, past
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conjecturing
present participle
verb (used without object)
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conjectures,
present (3rd person singular)
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conjectured,
past participle, past
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conjecturing
present participle
noun
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the formation of conclusions from incomplete evidence; guess
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the inference or conclusion so formed
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obsolete interpretation of occult signs
verb
Synonym Usage
See guess.
Other Word Forms
Derived Forms
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conjecturernoun
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misconjectureverb
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preconjectureverb (used with object)
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conjecturableadjective
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nonconjecturableadjective
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unconjecturableadjective
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unconjecturedadjective
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conjecturablyadverb
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nonconjecturablyadverb
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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conjecturesimple
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conjecturessimple
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have conjecturedperfect
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has conjecturedperfect
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am conjecturingprogressive
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are conjecturingprogressive
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is conjecturingprogressive
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have been conjecturingperfect progressive
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has been conjecturingperfect progressive
Past
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conjecturedsimple
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had conjecturedperfect
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was conjecturingprogressive
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were conjecturingprogressive
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had been conjecturingperfect progressive
Future
Etymology
Origin of conjecture
First recorded in 1350–1400; (for the noun) Middle English, from Middle French, from Latin conjectūra “inference, reasoning,” from conject(us) “thrown together” (past participle of conicere, conjicere “to throw together, form a conclusion,” from con- con- + -icere, -jicere, combining form of jacere “to throw”) + -ūra -ure; (for the verb) late Middle English conjecturen, from Middle French, from Late Latin conjecturāre, derivative of the noun
Explanation
Can you guess what conjecture means? It's a word to use when you are not sure of something and have to "guess or surmise." You can see how the word conjecture means that you create a theory or opinion about something without basing it in fact because the original definition of conjecture, from Old French, is "interpretation of signs and omens." Since signs and omens are pretty subjective, it makes sense that the word would then move to its current meaning. However, even though it only seems like weather reports are conjectures, they are actually based on evidence!
Vocabulary lists containing conjecture
Narrative of the Life of Frederick Douglass
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Their Eyes Were Watching God
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Grade 12, List 2
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Schnoebelen said that while the speculating on the origins of the statue is all conjecture at this point, she does enjoy the attention the statue has brought to this particular period of art.
From Los Angeles Times ● Aug. 14, 2026
One of the key reasons the Jacobian conjecture is so intriguing is that, in theory, it should be easy to find a counterexample.
From Science Daily ● Aug. 6, 2026
Unlike Simpson’s case, which ended in acquittals, the kidnapping attracted a new generation of amateur sleuths, livestreaming hours of content, conjecture and rumor each day to hundreds of thousands of online followers.
From The Wall Street Journal ● Aug. 2, 2026
The award for Tsimerman recognized his work, among other achievements, in helping to prove the André-Oort conjecture, a longstanding problem in geometry, the University of Toronto said.
From The Wall Street Journal ● Jul. 24, 2026
But all that is merely conjecture; no history books survived to tell the tale.
From "Ash" by Malinda Lo
But we have reached the point where famous math conjectures that stood for decades seem to be falling every day.
From The Wall Street Journal ● Aug. 1, 2026
Leaving the hard numbers aside, conjectures about the effects of AI on individual companies are exactly that — conjectures.
From Los Angeles Times ● Feb. 6, 2026
"This unprecedentedly clear signal of the black hole merger known as GW250114 puts to the test some of our most important conjectures about black holes and gravitational waves," Isi said.
From Science Daily ● Dec. 8, 2025
A lawyer for the New Jersey senator said the justice department claims were "baseless" and "bizarre conjectures".
From BBC ● Jan. 2, 2024
There is an idea—strange, haunting, evocative—one of the most exquisite conjectures in science or religion.
From "Cosmos" by Carl Sagan
Erdős conjectured that the maximum number of pairs, suggested by a gridlike system, could increase only slightly faster than the number of dots.
From The Wall Street Journal ● Jun. 14, 2026
Some legal observers have conjectured the 8th Circuit’s reversal of her injunction prompted her to stay her hand, over a concern that the appeals court would overrule her again.
From Los Angeles Times ● Feb. 5, 2026
But, for an elusive conjectured class of materials, physicists have now shown that the surface previously thought to be "featureless" holds an unmistakable signature that could lead to the first definitive observation.
From Science Daily ● Jan. 16, 2024
“Is there a universal basis for selection? Is there a more quantitative formalism underlying this conjectured conceptual equivalence—a formalism rooted in the transfer of information?,” they ask of the world’s disparate phenomena.
From Salon ● Oct. 22, 2023
If the sacrifice was not accepted, Bobby conjectured, Byrne would be lost; but if he did accept it, he’d also be lost.
From "Endgame" by Frank Brady
The outlay had some crypto followers conjecturing that he meant to consolidate the industry in his own hands.
From Los Angeles Times ● Nov. 9, 2022
"Rather than conjecturing whether Xi would restrain actions before the party congress, it is more realistic to analyse its daily military activities and make preparations accordingly," the official added.
From Reuters ● Feb. 23, 2022
Even the former commander of U.S. forces in Afghanistan, Gen. Stanley McChrystal, talked about "insurgent math," conjecturing that for every innocent person killed, the U.S. created 10 new enemies.
From Salon ● Sep. 20, 2021
It aims to understand an athlete’s brilliance by turning his game inside out, flipping and reversing it, conjecturing about and psychologizing him, close reading the repetitive motion, quirks, and kinks, breaking down Mr. McEnroe’s breakdowns.
From New York Times ● Aug. 21, 2018
The rest of the evening was spent in conjecturing how soon he would return Mr. Bennet’s visit, and determining when they should ask him to dinner.
From "Pride and Prejudice" by Jane Austen
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
