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.
That implies more unpredictable news and oil-market volatility ahead.
From MarketWatch ● Jul. 24, 2026
Residents have described scenes like a "war-zone", while the regional prefect Sophie Brocas called the blaze an "XXL wildfire, unpredictable and voracious".
From Barron's ● Jul. 24, 2026
The earnings outlook for memory chip makers is also inherently unpredictable.
From The Wall Street Journal ● Jul. 23, 2026
Still, the blooms are notoriously unpredictable, Tam said.
From Los Angeles Times ● Jul. 10, 2026
What struck him now was the realization that, in a winding and utterly unpredictable way, he might have accomplished his goal.
From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin
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.