Webster's Revised Unabridged Dictionary · 1913

Guess

Guess (ges) , transitive verb

[Old English gessen; akin to Danish gisse, Swedish gissa, Icelandic gizha, Dutch gissen: compare Danish giette to guess, Icelandic geta to get, to guess. Probably originally, to try to get, and akin to English get. See Get.]

1.
To form an opinion concerning, without knowledge or means of knowledge; to judge of at random; to conjecture.
First, if thou canst, the harder reason guess. — Pope
2.
To judge or form an opinion of, from reasons that seem preponderating, but are not decisive.
We may then guess how far it was from his design. — Milton
Of ambushed men, whom, by their arms and dress, To be Taxallan enemies I guess. — Dryden
3.
To solve by a correct conjecture; to conjecture rightly; as, he who guesses the riddle shall have the ring; he has guessed my designs.
4.
To hit upon or reproduce by memory. [Obsolete]
Tell me their words, as near as thou canst guess them. — Shakespeare
5.
To think; to suppose; to believe; to imagine; -- followed by an objective clause.
Not all together; better far, I guess, That we do make our entrance several ways. — Shakespeare
But in known images of life I guess The labor greater. — Pope

Guess , intransitive verb

To make a guess or random judgment; to conjecture; -- with at, about, etc.
This is the place, as well as I may guess. — Milton

Guess , noun

An opinion as to anything, formed without sufficient or decisive evidence or grounds; an attempt to hit upon the truth by a random judgment; a conjecture; a surmise.
A poet must confess His art 's like physic -- but a happy guess. — Dryden