What does "surmise" mean?

Additional senses

1. 2.To imagine without certain knowledge; to infer on slight grounds; to suppose, conjecture, or suspect; to guess. It wafted nearer yet, and then she knew That what before she but surmised, was true. Dryden. This change was not wrought by altering the form or position of the earth, as was surmised by a very learned man, but by dissolving it. Woodward.