one-off

详细解释:a. 一次性的
n. 一次性事物
【经】 专为某一顾客的需要特制的

英语解释：

名词 one-off:

a happening that occurs only once and is not repeated

例句：

Her novel was just a one-off -- she never wrote anything as good as that again.她的小说是她绝无仅有的作品--後来她再也没写出那样好的东西。