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.
That said, he could also do unpredictable, chaotic and sometimes offensive things.
From Salon ● Oct. 16, 2026
Of the four-person ensemble, I was most intrigued by Rachna Khatau, the wild card of the group whose roles are the most slyly scheming and unpredictable.
From Los Angeles Times ● Oct. 13, 2026
“By making air travel increasingly unpredictable and raising security concerns around international events, the Houthis are seeking to impose economic costs on Saudi Arabia that extend well beyond the physical damage inflicted,” Mehvar said.
From MarketWatch ● Oct. 12, 2026
To hedge against the unpredictable nature of securing computing power, some companies are signing contracts for more capacity than they need.
From The Wall Street Journal ● Oct. 10, 2026
We’d taken him on a dozen rides through the open pasture, but he was inexperienced, skittish, unpredictable.
From "Educated" by Tara Westover
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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.