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.
“The world has become a more unpredictable place, and I think it is absolutely clear that Europe needs to increase its defense profile,” Ola Källenius told The Wall Street Journal Friday.
From The Wall Street Journal • May 15, 2026
As space agencies prepare for future Moon exploration, scientists are working to better understand these unpredictable solar events.
From Science Daily • May 14, 2026
The season is the work of reporters who’ve covered the Supreme Court for decades, pulling the curtain back on the most unpredictable vote on the most powerful court in modern history.
From Slate • May 13, 2026
Beyond diplomatic niceties and behind closed doors, Beijing will be looking for small, concrete achievements, analysts said, but will stay "realistically pragmatic" given Trump's unpredictable nature.
From Barron's • May 8, 2026
But Nighthand was unpredictable, and angered, and six feet ten inches tall, so he did not say it aloud.
From "Impossible Creatures" by Katherine Rundell
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.
