Etymology From Middle English uncerteyn. By surface analysis, un- + certain.
1
Not certain; unsure.
Conſider man without the protection and conduct of a ſuperior Being, and he is ſecure of nothing that he enjoys in this world, and uncertain of every thing that he hopes for.1664, John Tillotson, “Sermon I. The Wisdom of Being Religious. Job XXVIII. 28.”, in The Works of the Most Reverend Dr. John Tillotson, Late Lord Archbishop of Canterbury: […], 8th edition, London: […] T. Goodwin, B[enjamin] Tooke, and J. Pemberton, […]; J. Round […], and J[acob] Tonson] […], published 1720, →OCLC, page 20:
2
Not known for certain; questionable.
Tomorrow's weather is uncertain.
3
Not yet determined; undecided.
4
Variable and subject to change.
5
Fitful or unsteady.
Turning back, then, toward the basement staircase, she began to grope her way through blinding darkness, but had taken only a few uncertain steps when, of a sudden, she stopped short and for a little stood like a stricken thing, quite motionless save that she quaked to her very marrow in the grasp of a great and enervating fear.1914 November, Louis Joseph Vance, “An Outsider […]”, in Munsey’s Magazine, volume LIII, number II, New York, N.Y.: The Frank A[ndrew] Munsey Company, […], published 1915, →OCLC, chapter III (Accessory After the Fact), page 382, column 1:
6
Unpredictable or capricious.
O, woman! in our hours of ease, / Uncertain, coy, and hard to please, / And variable as the shade / By the light quivering aspen made; […]1808 February 22, Walter Scott, “Canto Sixth. The Battle.”, in Marmion; a Tale of Flodden Field, Edinburgh: […] J[ames] Ballantyne and Co. for Archibald Constable and Company, […]; London: William Miller, and John Murray, →OCLC, stanza XXXI, page 362:
Thinking about the uncertain refines our perception of the certain, and generally this takes place in a framework in which the uncertain is the future and the certain is the present.2011, John Lyons, The Phantom of Chance: From Fortune to Randomness in Seventeenth-Century French Literature: