Definition of "surmise"

But ſurely no Man whatſoever ought in Justice or good Manners to be charged with Principles he actually diſowns, unleſs his Practices do openly and without the leaſt Room for Doubt, contradict his Profeſſion: Not upon ſmall Surmiſes, or becauſe he has the Miſfortune to have Ill Men ſometimes agree with him in a few general Sentiments.

1721, anonymous [Jonathan Swift], “The Sentiments of a Church of England-man with Respect to Religion and Government. Written in the Year, 1708”, in Miscellanies in Prose and Verse, 4th edition, Dublin: Printed by S. Fairbrother, book-seller, and are to be sold at his shop in Skinner-Row, over against the Tholsel, page 61

The meeting had been devoid of incident. No word had been said to give me anything to think about, and any surmises I might make were unwarranted. I was intrigued.

1919, W[illiam] Somerset Maugham, chapter 32, in The Moon and Sixpence: A Novel (Heinemann's Colonial Library of Popular Fiction), London: William Heinemann

In short, the chances of the Princes Street terminal's survival seem unsure, though at the moment these views are no more than surmise.

1962 April, “Talking of Trains: The future of Princes Street”, in Modern Railways, page 227

My Thought, whoſe Murther yet is but fantaſticall, / Shakes ſo my ſingle ſtate of Man, / That Function is ſmother'd in ſurmiſe, / And nothing is, but what is not.

c. 1606?, William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies, London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, act I, scene iii, page 133

Then felt I like some watcher of the skies / When a new planet swims into his ken; / Or like stout Cortez when with eagle eyes / He star'd at the Pacific—and all his men / Look'd at each other with a wild surmise— / Silent, upon a peak in Darien.

1816 December 1, John Keats, “[Sonnets.] Sonnet XI. On First Looking into Chapman’s Homer.”, in Poems, London: […] [Charles Richards] for C[harles] & J[ames] Ollier, […], published 3 March 1817; reprinted in Poems (The Noel Douglas Replicas), London: Noel Douglas, 1927, page 89