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.
The IMF chief said regulators should be on alert for any signs of instability in the financial system as a consequence of the conflict.
From The Wall Street Journal • Apr. 9, 2026
Their biggest weakness is instability, which causes the information they process to quickly break down.
From Science Daily • Apr. 8, 2026
Philippa said the British government and Violet's family wrote to Mussolini following the attack to thank him and congratulate him on surviving, and to emphasise her mental instability.
From BBC • Apr. 7, 2026
Some of what has impacted the unimpressive growth of the addressable audience for home entertainment has been the instability of the market.
From MarketWatch • Mar. 30, 2026
Soon there will be signs of emotional instability and forgetfulness, the first symptoms of the burnout.
From "Flowers for Algernon" by Daniel Keyes
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.
