- not definitely ascertainable or fixed, as in time of occurrence, number, dimensions, or quality.
- not confident, assured, or free from hesitancy: an uncertain smile.
- not clearly or precisely determined; indefinite; unknown: a manuscript of uncertain origin.
- vague; indistinct; not perfectly apprehended: an abstruse novel with uncertain themes.
- subject to change; variable; capricious; unstable: a person of uncertain opinions.
- ambiguous; unreliable; undependable: Her loyalties are uncertain.
- dependent on chance or unpredictable factors; doubtful; of unforeseeable outcome or effect.
- unsteady or flickering, as light; of changing intensity or quality.
Origin of uncertain
1. Uncertain, insecure, precarious imply a lack of predictability. That which is uncertain is doubtful or problematical; it often involves danger through an inability to predict or to place confidence in the unknown: The time of his arrival is uncertain. That which is insecure is not firm, stable, reliable, or safe, and hence is likely to give way, fail, or be overcome: an insecure foundation, footing, protection. Precarious suggests great susceptibility to failure, or exposure to imminent danger: a precarious means of existence.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- not able to be accurately known or predictedthe issue is uncertain
- (when postpositive, often foll by of) not sure or confident (about)a man of uncertain opinion
- not precisely determined, established, or decideduncertain plans
- not to be depended upon; unreliablean uncertain vote
- liable to variation; changeablethe weather is uncertain
- in no uncertain terms
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for uncertainness
Online Etymology Dictionary, © 2010 Douglas Harper
Idioms and Phrases with uncertainness
see in no uncertain terms.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.