conjecture

n. guess, supposition, assumption

v. hypothesize, guess, surmise, infer, speculate

In mathematics, a conjecture is a mathematical statement which appears likely to be true, but has not been formally proven to be true under the rules of mathematical logic. Once a conjecture is formally proven true it is elevated to the status of theorem and may be used afterwards without risk in the construction of other formal mathematical proofs. Until that time, mathematicians may use the conjecture on a provisional basis, but any resulting work is itself conjectural until the underlying conjecture is cleared up.
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n. conjecture, guess, surmise

v. surmise

v. conjecture, hypothesize, guess, surmise, infer, speculate

(v. t.)
To arrive at by conjecture; to infer on slight evidence; to surmise; to guess; to form, at random, opinions concerning.
  

(v. i.)
To make conjectures; to surmise; to guess; to infer; to form an opinion; to imagine.
  

(n.)
An opinion, or judgment, formed on defective or presumptive evidence; probable inference; surmise; guess; suspicion.