instability
Americannoun
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the quality or state of being unstable; lack of stability or firmness.
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the tendency to behave in an unpredictable, changeable, or erratic manner.
emotional instability.
noun
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lack of stability or steadiness
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tendency to variable or unpredictable behaviour
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physics a fast growing disturbance or wave in a plasma
Etymology
Origin of instability
1375–1425; late Middle English instabilite < Latin instabilitās. See in- 3, stability
Explanation
Instability is the quality of not being stable, balanced, or predictable. If you've ever walked out onto a diving board, you've probably noticed its instability — meaning the board bends and bounces as you move. Instability comes from the Middle French word instabilite, meaning "unsteadiness." Instability can refer to objects that are not stable, but it can also describe unpredictable situations or relationships. For example, you might hear people talk about economic instability. Or if your behavior at school grows erratic and unpredictable, you might be asked to speak to a therapist about your psychological instability.
Vocabulary lists containing instability
Southeast Asia - Middle School
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Southeast Asia - High School
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Second Democratic Debate 20 words
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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.
“Over the longer term, it creates a kind of chronic instability that makes it extremely difficult to engage in healthcare, maintain treatment, or make progress toward housing,” Henwood said.
From Los Angeles Times • Apr. 16, 2026
It’s a remarkable feat in the face of the ongoing instability in the Middle East.
From Barron's • Apr. 15, 2026
Second, private-credit funds do little of the maturity transformation that lies at the heart of banking instability.
From MarketWatch • Apr. 13, 2026
"For the past five decades, we both have been facing instability in our countries in the form of refugees," Durrani says.
From BBC • Apr. 10, 2026
Blandly telling him that I kept my hair long to avoid confusion with American Air Force personnel proved my mental instability.
From "Double Helix" by James D. Watson
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.
