conjecture

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Inference or judgment based on inconclusive or incomplete evidence; guesswork.
2. n. A statement, opinion, or conclusion based on guesswork: The commentators made various conjectures about the outcome of the next election.
3. v. To infer from inconclusive evidence; guess.
4. v. To make a conjecture.

Century Dictionary and Cyclopedia

1. n. The act of forming an opinion without definite proof; a supposition made to account for an ascertained state of things, but as yet unverified; an opinion formed on insufficient presumptive evidence; a surmise; a guess.
2. n. Suspicious surmise; derogatory supposition or presumption.
3. n. Synonyms Supposition, hypothesis, theory.
4. To form (an opinion or notion) upon probabilities or upon slight evidence; guess: generally governing a clause.
5. Synonyms Imagine, Conjecture, Surmise, Guess, Presume, fancy, divine. Imagine literally expresses pure speculation, and figuratively expresses an idea founded upon the slightest evidence: as, I imagine that you will find yourself mistaken. Conjecture is something like a random throw of the mind; it turns from one possibility to another, and perhaps selects one, almost arbitrarily. Surmise has often the same sense as conjecture; it sometimes implies a suspicion, favorable or otherwise: as, I surmise that his motives were not good. Guess suggests a riddle, the solution of which is felt after by the mind—a question, as to which we offer an opinion, but not with confidence, because the material for a judgment is confessedly insufficient. To presume is to base a tentative or provisional opinion on such knowledge as one has, to be held until it is modified or overthrown by further information.
6. To form conjectures; surmise; guess.

Wiktionary

1. n. formal A statement or an idea which is unproven, but is thought to be true; a guess.
2. n. formal A supposition based upon incomplete evidence; a hypothesis.
3. n. mathematics, philology A statement likely to be true based on available evidence, but which has not been formally proven.
4. n. obsolete Interpretation of signs and omens.
5. v. formal, intransitive To guess; to venture an unproven idea.

GNU Webster's 1913

1. n. An opinion, or judgment, formed on defective or presumptive evidence; probable inference; surmise; guess; suspicion.
2. v. To arrive at by conjecture; to infer on slight evidence; to surmise; to guess; to form, at random, opinions concerning.
3. v. To make conjectures; to surmise; to guess; to infer; to form an opinion; to imagine.

WordNet 3.0

1. v. to believe especially on uncertain or tentative grounds
2. n. reasoning that involves the formation of conclusions from incomplete evidence
3. n. a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)
4. n. a message expressing an opinion based on incomplete evidence