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unsustainable

American  
[uhn-suh-stey-nuh-buhl] / ˌʌn səˈsteɪ nə bəl /

adjective

  1. not sustainable; not to be supported, maintained, upheld, or corroborated.


Other Word Forms

Etymology

Origin of unsustainable

1670–80; un- 1 + sustainable ( def. )

Explanation

If something is unsustainable, there's just no way to keep doing it at the same rate or in the same way. You've been able to keep your new puppy from whining by petting her all night long, but that's unsustainable. When you can bear something, or continue it, it's sustainable, from the Latin root sustinere, "bear or endure." Unsustainable things can't go on, like unsustainable economic growth that's bound to level out or drop eventually, or an unsustainable expectation that you will always have a perfect grade point average. When it comes to the environment, practices that cause long-term harm or deplete resources are also unsustainable: "Ending unsustainable fishing practices successfully revived the salmon population."

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Vocabulary lists containing unsustainable

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.

See Examples For:

NFU Scotland president Andrew Connon says the situation is "totally unsustainable" and the worst crisis that pig farmers have experienced in more than 50 years.

From BBC Jul. 10, 2026

He's been losing about £40 for each animal he sells, meaning his weekly loss is around £10,000 which he describes as unsustainable.

From BBC Jul. 10, 2026

Reintroducing tigers could put "a bit of a brake" on unsustainable development in the Cardamoms, said Tom Gray, of WWF's global tiger programme.

From Barron's Jul. 8, 2026

In each case, a low price-to-earnings ratio disguised an unsustainable uptick in profits.

From MarketWatch Jul. 6, 2026

Thus language-games do not simply succeed, progress, pay, or prove their worth; they can also become unsustainable if the facts change.

From "The Invention of Science" by David Wootton

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