unless

unless is one of the 1000 most common headwords.
 unless

Pronunciation

• IPA (key): /ənˈlɛs/
•  Audio (US) (file)

Preposition

 Prepositionunless
1. If you say that ${\displaystyle x}$ is true unless ${\displaystyle y}$, ${\displaystyle x}$ is true only if ${\displaystyle y}$ does not happen or is not true.
I'll be there at 8:30 unless the train is late.
Unless you help, we won't finish on time.