conjecture
/kən-ˈjek-chər/
noun
inference formed without proof or sufficient evidence
a conclusion deduced by surmise or guesswork
a proposition (as in mathematics) before it has been proved or disproved
The criminal's motive remains a matter of conjecture.
verb
to arrive at or deduce by surmise or guesswork : guess
to make conjectures as to
to form conjectures
scientists conjecturing that a disease is caused by a defective gene
noun phrase
—used to say that something is based on an idea formed without proof or sufficient evidence