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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unconjecturedadjective
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conjecturernoun
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preconjectureverb (used with object)
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conjecturablyadverb
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unconjecturableadjective
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nonconjecturablyadverb
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conjecturableadjective
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misconjectureverb
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nonconjecturableadjective
Conjugated Forms
Present
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have conjecturedperfect
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has conjecturedperfect 3rd person singular
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am conjecturingprogressive 1st person singular
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is conjecturingprogressive 3rd person singular
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are conjecturingprogressive
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have been conjecturingperfect progressive
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has been conjecturingperfect progressive 3rd person singular
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conjecturessingular 3rd person
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conjecturingparticiple
Past
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had conjecturedperfect
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had been conjecturingperfect progressive
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were conjecturingprogressive plural
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was conjecturingprogressive singular
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conjecturedsimple
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conjecturedparticiple
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.
Erdős showed in 1946 that arranging those dots in a grid produced a certain number of pairs, and his conjecture was that no arrangement could do much better.
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
The study introduces what the authors call the "entropy conjecture" to highlight a key problem in many existing arguments.
From Science Daily • May 3, 2026
While this part showed some optimistic conjecture, Kirby said a combined airline’s need for new planes would support domestic manufacturing.
From MarketWatch • Apr. 27, 2026
What happened next is a twisted braid of mixed signals, distrust, miscommunication, and conjecture.
From "The Gene" by Siddhartha Mukherjee
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.
