one-off

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++ˈone-off1 adjective [only before noun] British English  ONLYhappening or done only once, not as part of a regular series 只发生一次的；一次完成的 SYN American English one-shot It’s yours for a one-off payment of only £200. 一次性仅付200英镑，它就是你的了。

Examples from the Corpus

one-off• Many extremely interesting publications on art currently only exist as a one-off draft.• So far, most discounters have stuck to selling food, though Aldi does use one-off promotions of clothing to attract customers.• In fact the whole exercise was fairly straight forward, except for one problem which required a one-off solution.• They will play a one-off Test and three one-day internationals between March 10-25.• It's the one-off thug who normally panics and lashes out.• Verdict: Recommended for one-off use in conditions where you dare not risk an expensive camera.one-off payment• In addition, a number of one-off payments were made to the Partnerships.• This is a one-off payment which protects the lender in case you default on the loan.ˌone-ˈoff2 noun [countable] British English  1  DIFFERENTsomething that is done or made only once 只做过一次的事；一次性事物 The deal was a one-off. 这项交易是一次性的。2. informalDIFFERENT someone who is completely different from anyone else 与他人完全不同者

Examples from the Corpus

one-off• Ever since 1959, and Bomb, Miles had been experimenting with small magazines and one-offs.• Some were marked as regular orders, some as one-offs.

ˈone-off1 adjectiveˌone-ˈoff2 nounChineseSyllable  

once, Corpus part done not or as only happening

one-off

I

ˈone-off¹ adjective [only before noun] British English
happening or done only once, not as part of a regular series
   SYN  one-shot American English:
    It’s yours for a one-off payment of only £200.

II

ˌone-ˈoff² noun [countable] British English
1. something that is done or made only once:
    The deal was a one-off.
2. informal someone who is completely different from anyone else