verb
To reach a partly (or totally) unconfirmed conclusion; to engage in conjecture; to speculate.
To solve by a correct conjecture; to conjecture rightly.
(chiefly US) to suppose, to imagine (introducing a proposition of uncertain plausibility).
(colloquial) To think, conclude, or decide (without a connotation of uncertainty). Usually in first person: "I guess".
(obsolete) To hit upon or reproduce by memory.
noun
A prediction about the outcome of something, typically made without factual evidence or support.