conjecture
Americannoun
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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)
verb (used without object)
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:
The events in the Rex Rooms, controversy and fallout, culminating with Stokes' sudden retirement, announced in the middle of a bowling spell, have led to claims, conspiracies and conjecture.
From BBC ● Jun. 29, 2026
Our research supports this conjecture, as we found that companies with more cheap stock experienced lower stock returns over longer horizons after going public.
From Salon ● Jun. 13, 2026
Most people who tackled this problem tried to prove Erdős’s conjecture, rather than disprove it.
From The Wall Street Journal ● May 30, 2026
Additionally, multiple commentators conjecture that his hostility to wind originated in 2011, when he groused that an offshore wind farm would be visible from one of his golf courses in Scotland.
From Los Angeles Times ● May 14, 2026
Who is Peter Van Houten to assert as fact the conjecture that our labor is temporary?
From "The Fault in Our Stars" by John Green
"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
A viral video stirred conjectures of ill will between Lili Reinhart and Sydney Sweeney.
From Los Angeles Times ● Nov. 14, 2023
So to conclude: conjectures about advanced or intelligent life are on a far shakier ground than those about simple life.
From Scientific American ● Jun. 1, 2023
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
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
Greene conjectured that the fires were caused by “lasers or blue beams of light...coming down to Earth I guess.”
From Los Angeles Times ● Jul. 17, 2023
International master George Koltanowski conjectured that Bobby just didn’t trust people and didn’t want to be cheated: “There’s a word for it in German: Verfolgungswahnsinn,” he said.
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
Preservationists angrily reject the mayor’s figures, conjecturing a far lower cost to keep the bridge open just for pedestrians and bikes.
From New York Times ● Mar. 12, 2018
They had a pleasant five minutes conjecturing about how much was in the bank.
From "A Tree Grows in Brooklyn" by Betty Smith
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.
