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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Speak
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Twenty Thousand Leagues Under the Sea
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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.
Fanning’s co-star Johnson told The Envelope via email he loved working with her, “first because she’s a great actor. She is present and unpredictable in scenes. She is real,” he shared.
From Los Angeles Times ● Aug. 19, 2026
A lot of factors are combining to make this a highly unpredictable midterm:
From The Wall Street Journal ● Aug. 12, 2026
Lax safety standards and unpredictable weather are the main reasons for the disasters.
From Barron's ● Aug. 12, 2026
Like all good wingers he is unpredictable and can go on either the inside or outside, which means it is hard for defenders to know if he is going to cross the ball or shoot.
From BBC ● Aug. 10, 2026
If you concentrate on controversy, then it begins to look as if progress in science is arbitrary and unpredictable.
From "The Invention of Science" by David Wootton
Definitions 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.
