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.
Benjamin Henwood, a USC social work researcher and co-author of the paper, said that kind of instability can cause people to lose medications, documents, belongings and connections to outreach workers and care providers.
From Los Angeles Times • Apr. 16, 2026
The country has the largest oil reserves in Africa but the years of fighting and instability have left them chronically underdeveloped.
From The Wall Street Journal • Apr. 15, 2026
It’s a remarkable feat in the face of the ongoing instability in the Middle East.
From Barron's • Apr. 15, 2026
McKechnie - who once said he treats "broken-down athletes who are almost like reclamation projects" - had discovered Hargreaves' knee issues were caused by pelvic instability and therefore got him working to strengthen his core.
From BBC • Apr. 14, 2026
This brought on a downward spiral of mental instability.
From "Lincoln's Last Days: The Shocking Assassination that Changed America Forever" by Bill O'Reilly
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.
