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.
Fittingly, the art on the album’s cover is a 15th-century rendering of a knight on a quest, and the outcome of quests are notoriously unpredictable.
From The Wall Street Journal ● Aug. 14, 2026
Lax safety standards and unpredictable weather are the main reasons for the disasters.
From Barron's ● Aug. 12, 2026
Hot weather can make travel unpredictable, and access issues can waste valuable time on an already exhausting day.
From BBC ● Aug. 11, 2026
Since the markets are so unpredictable, it makes sense to divide your eggs among many baskets rather than bet on just one.
From MarketWatch ● Aug. 6, 2026
Among his children, he was known for being hotheaded and unpredictable, but equal parts loving.
From "Americanized" by Sara Saedi
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.
