conjecture

American  

[kuhn-jek-cher] / kənˈdʒɛk tʃər /

noun

1. the formation or expression of an opinion or theory without sufficient evidence for proof.

2. an opinion or theory so formed or expressed; guess; speculation.

   Synonyms:

   hypothesis, theory, supposition, inference, surmise

3. Obsolete. the interpretation of signs or omens.

---

verb (used with object)

conjectured, conjecturing

1. to conclude or suppose from grounds or evidence insufficient to ensure reliability.

   Synonyms:

   presume, suppose, surmise

verb (used without object)

conjectured, conjecturing

1. to form conjectures.

conjecture British  

/ kənˈdʒɛktʃə /

noun

1. the formation of conclusions from incomplete evidence; guess

2. the inference or conclusion so formed

3. obsolete interpretation of occult signs

---

verb

1. to infer or arrive at (an opinion, conclusion, etc) from incomplete evidence

Related Words

See guess.

Other Word Forms

• conjecturable adjective
• conjecturably adverb
• conjecturer noun
• misconjecture verb
• nonconjecturable adjective
• nonconjecturably adverb
• preconjecture verb (used with object)
• unconjecturable adjective
• unconjectured adjective

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!

Example Sentences

His defence team countered that Duterte had murdered no one and that the prosecution's argument was based on "hearsay" and "conjecture", falling far short of the bar needed to confirm the charges against him.

From Barron's • Feb. 27, 2026

In math, Ono is known for his work on a range of topics across number theory, from Ramanujan’s congruences to the umbral moonshine conjecture.

From The Wall Street Journal • Dec. 4, 2025

Nearly everything else ever written about the family is conjecture spun from the scraps of information that exist, such as Shakespeare’s will leaving nothing to his wife other than “his second-best bed.”

From Los Angeles Times • Nov. 25, 2025

Strange Brew added that it was "not in line with our values to exclude Oi Va Voi and Zohara from performing on the basis of conjecture by another group about their views".

From BBC • Nov. 19, 2025

For all its audacity, Lawrence’s conjecture about the potential to create new radioisotopes was correct.

From "Big Science" by Michael Hiltzik

Related Words

• guesswork
• hunch
• hypothesis
• inference
• supposition