unless
un-LES/ənˈlɛs/
- 1Except if; if not: introduces the one condition under which the main statement would not happen or not be true.
The flight will depart on time unless the weather worsens.
Employees may not share client data unless the client has given written consent.
UsageUse the present for a future condition: unless it rains (not
incorrect: unless it will rain). It means if not, so the clause is usually positive.
Use it in a sentence
Write your own sentence with unless, and AI will tell you whether it fits and which meaning you used.
Origin
Middle English unlesse began as on lesse (today's "on" + "less"), taken from "(not) on lesse (than)," that is, "(not) on a less compelling condition (than)." Because the word went unstressed and carried a negative sense, its "on" turned into "un-."