To change imperceptibly from one gradation of tone etc. to another.
To arrange in order of grades.
To bring to a certain strength or grade of concentration.
to suppose (introducing a proposition of uncertain plausibility).
To solve by a correct conjecture; to conjecture rightly.
To reach a partly (or totally) unqualified conclusion.
To think, conclude, or decide (without a connotation of uncertainty). Usually in first person: "I guess".
A prediction about the outcome of something, typically made without factual evidence or support.