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Synonyms

instability

American  
[in-stuh-bil-i-tee] / ˌɪn stəˈbɪl ɪ ti /

noun

  1. the quality or state of being unstable; lack of stability or firmness.

  2. the tendency to behave in an unpredictable, changeable, or erratic manner.

    emotional instability.


instability British  
/ ˌɪnstəˈbɪlɪtɪ /

noun

  1. lack of stability or steadiness

  2. tendency to variable or unpredictable behaviour

  3. physics a fast growing disturbance or wave in a plasma

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.

Keep Reading on Vocabulary.com

Vocabulary lists containing instability

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 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

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

Tokyo stands on the boundary of three tectonic plates in a country already well known for its seismic instability.

From "A Short History of Nearly Everything" by Bill Bryson