a one-off


An isolated occurrence; something that happens just once. Oh, that class was a one-off—my interest in French was dead by the time the semester ended. I swear, I don't like him—our kiss was just a one-off! Their performance was just a one-off—they won't be touring.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

a ˌone-ˈoff

(British English)
1 a thing that is made or that happens only once and not regularly: This plate is a one-off produced by Minton in 1898.‘Are they going to do another concert in the church this year?’ ‘I don’t think so. It was just a one-off.’
2 (informal, humorous) a person who is quite unlike other people: There’ll never be another Charlie Chaplin. He was a one-off.
Farlex Partner Idioms Dictionary © Farlex 2017
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