instability

noun

in·​sta·​bil·​i·​ty ˌin(t)-stə-ˈbi-lə-tē 

: the quality or state of being unstable

especially : lack of emotional or mental stability

Synonyms of instability

• unsteadiness
• precariousness
• unstableness
• insecurity

Examples of instability in a Sentence

Investors are worried about the current instability of the stock market.

The patient has a history of emotional instability.

Recent Examples on the Web

That moisture is being pulled northward by an upper-level trough — a low-pressure area in the atmosphere — and the resulting instability may produce thunderstorms and showers. — Iris Kwok, Los Angeles Times, 27 Aug. 2026

At their worst, a cloud of quarterback instability overshadowed the season. — David Troy Outkick, FOXNews.com, 23 Aug. 2026

With Fenway Sports Group CEO of football Michael Edwards leaving last month and sporting director Richard Hughes expected to follow after this summer’s window, there’s no shortage of uncertainty and instability above Iraola. — James Pearce, New York Times, 23 Aug. 2026

During this time of political instability the government ordered too few vaccine doses. — Kathryn H. Jacobsen, The Conversation, 21 Aug. 2026

Word History

First Known Use

15th century, in the meaning defined above

Rhymes for instability

• affability
• audibility
• bistability
• capability
• changeability
• contractility
• credibility
• culpability
• disability
• disutility
• durability
• fallibility

Kids Definition

instability

noun

in·​sta·​bil·​i·​ty ˌin(t)-stə-ˈbil-ət-ē 

: the quality or state of being unstable

Medical Definition

instability

noun

in·​sta·​bil·​i·​ty ˌin(t)-stə-ˈbil-ət-ē 

plural instabilities

: the quality or state of being unstable

especially : lack of emotional or mental stability