unpredictable
Americanadjective
noun
adjective
Other Word Forms
- unpredictability noun
- unpredictableness noun
- unpredictably adverb
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.
“It was always a concern but it was unpredictable because they didn’t have the legislative or regulatory basis,” Ross says.
From Barron's • Apr. 27, 2026
"We're dealing with a very unpredictable president," says Lownie.
From BBC • Apr. 24, 2026
It’s strange and unpredictable, but then again, any pop star should be.
From Salon • Apr. 24, 2026
Kelly, a statuesque presence in a dress, harness and boots, brings the horse to life with wild, unpredictable movements.
From Los Angeles Times • Apr. 21, 2026
“The fortune-teller may have a true gift, but the situation is unpredictable, and we must plan for various outcomes. As Agatha Swanburne once said, ‘Trust whom you like, but rely on yourself.’
From "The Unseen Guest" by Maryrose Wood
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.
