instability

American  

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

noun

• instabilities
  plural

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.

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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

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Other Word Forms

Noun Inflected Forms

• instabilities
  plural

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.

Example Sentences

See Examples For:

instability instabilities

While large investors are placing huge bets that airlines will do well, others are betting on the opposite and the instability is making stocks jump around wildly, the analyst says.

From The Wall Street Journal ● Aug. 26, 2026

“There’s just kind of a sense of instability and a little bit of ‘here we go again,’” she said.

From Los Angeles Times ● Aug. 25, 2026

Tiny differences in temperature, humidity, wind and atmospheric instability can determine whether a storm forms at all or where it moves.

From BBC ● Aug. 25, 2026

Aggressive expansions typically come with plenty of risk: an immediate strain on resources, profit instability, and possibly outgrowing the existing business model.

From Slate ● Aug. 24, 2026

“You’ll have to expect some emotional instability, after what they’ve been through. They were particularly ill prepared, coming from their life in the Capitol.”

From "Mockingjay" by Suzanne Collins

Those conditions could provide exactly what is needed for Kelvin-Helmholtz instabilities to form.

From Science Daily ● Aug. 8, 2026

These instabilities have been a major obstacle to improving fusion performance.

From Science Daily ● Jan. 4, 2026

Its present size and depth, approximately 350 km wide, line up well with predictions for these slow-moving mantle instabilities.

From Science Daily ● Nov. 25, 2025

The researchers reported their findings on May 11 in Nature Communications, underscoring the vast potential of machine learning and other artificial intelligence systems to quickly quash plasma instabilities.

From Science Daily ● Jun. 5, 2024

Trax's recovery from his psychological instabilities wasn't as definitive.

From Underground by Suelette Dreyfus

Related Words

• anxiety
• fluctuation
• insecurity
• uncertainty
• volatility
• vulnerability
• weakness