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.
But SpaceX and its fellow IPOs won’t behave like normal stocks for months, if not longer, and trading promises to be choppy and unpredictable.
From Barron's • May 22, 2026
Things are considerably less fraught, noisy and wildly unpredictable than they were last week.
From BBC • May 19, 2026
The misoprostol-only protocol has some downsides: It can be a bit more unpredictable, since it can take longer for a body to expel a pregnancy if it’s not prepped with mifepristone.
From Slate • May 18, 2026
“Her travel patterns continue to demonstrate the unpredictable movements of a dispersing wolf seeking a mate and territory of its own,” John Marchwick, of the educational group California Wolf Watch, said in a statement.
From Los Angeles Times • May 18, 2026
After so many years he was as unpredictable as ever.
From "Nectar in a Sieve" by Kamala Markandaya
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.
