unpredictable
Americanadjective
noun
adjective
Other Word Forms
Etymology
Origin of unpredictable
First recorded in 1855–60; un- 1 + predictable
Explanation
When something's unpredictable, it doesn't happen at expected times or it can't be predicted. If trains were unpredictable, they wouldn't follow a set schedule and you'd never know when one would arrive. The adjective unpredictable can also describe something that's unexpected or not known in advance. Your soccer team's skill level might be wildly unpredictable — from game to game your coach never knows what you guys will do. It can be an insult if someone calls you an unpredictable person. That means people can't rely on you for things, such as consistently good work or keeping your promises.
Vocabulary lists containing unpredictable
Power Prefix: un-
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Not only is IVF expensive in the U.S.—benefits provider Carrot puts the average cost per cycle at $23,474—it is unpredictable, with multiple rounds often required and no guarantee of success.
From The Wall Street Journal ● Nov. 5, 2026
A wave of intense and, at times, unpredictable storms exacerbated by the El Niño weather pattern has killed dozens, shuttered major airports and wiped out crops and infrastructure across a swathe of East Asia.
From BBC ● Nov. 4, 2026
Reality television personality Spencer Pratt jumped in a few months later, on the anniversary of the Palisades fire, establishing himself as an unpredictable presence on the campaign trail.
From Los Angeles Times ● Nov. 1, 2026
Unlike the controlled conditions of a laboratory, cosmic radiation is highly unpredictable.
From Science Daily ● Oct. 28, 2026
I had learned that human beings are frequently unpredictable.
From "The Boy on the Wooden Box" by Leon Leyson
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
