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.
Rather than the unpredictable hints that preceded the 2024 unwind, the BoJ has intervened more regularly so far this year and has been “more active in the market,” Getter told MarketWatch in a phone interview.
From MarketWatch • Jul. 2, 2026
Research and consulting firm Wood Mackenzie has tracked a related challenge: data centers consuming electricity in unpredictable ways.
From The Wall Street Journal • Jul. 2, 2026
Settings like this are a good place to start, since they’re controlled environments that involve plenty of repetition, rather than unpredictable elements.
From Barron's • Jun. 30, 2026
He insisted the unpredictable final 15 minutes of the game in Kansas City clearly showed neither side was looking to repeat the 'Disgrace of Gijon'.
From BBC • Jun. 28, 2026
With such unpredictable water conditions, researchers have difficulties not only properly recording where each object has been discovered, but also physically removing the objects.
From "Shipwrecked!" by Martin W. Sandler
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.
