unless

American  

[uhn-les, uhn-] / ʌnˈlɛs, ən- /

conjunction

1. except under the circumstances that.

   I'll be there at nine, unless the train is late.

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preposition

1. except; but; save.

   Nothing will come of it, unless disaster.

unless British  

/ ʌnˈlɛs /

conjunction

1. (subordinating) except under the circumstances that; except on the condition that

   they'll sell it unless he hears otherwise

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preposition

1. rare except

Etymology

Origin of unless

1400–50; late ME prepositional phrase on less (also o less(e) , earlier upon less ) on a lesser footing or condition (than); first used as a preposition and conjunction in the early 16th century; see on, less

Example Sentences

See Examples For:

unless

Don’t give up the bonus unless you determine that it really would leave you better off.

From MarketWatch ● Aug. 14, 2026

Under the Federal Advisory Committee Act, such groups automatically end after two years unless explicitly renewed.

From Los Angeles Times ● Aug. 13, 2026

With DoorDash for the coffee run and AI to answer the phone, there is little reason to bring in college kids unless they can pull their weight on meaningful tasks.

From The Wall Street Journal ● Aug. 13, 2026

The future of endangered species across the world could be affected unless the government brings in new laws soon, to make it easier to transfer animals around the globe, conservationists say.

From BBC ● Aug. 13, 2026

All I know is that he’s going for a drive, which he never does unless he’s got serious things on his mind.

From "Split the Sky" by Marie Arnold