unrepeatable
adjective uk/ˌʌn.rɪˈpiː.tə.bəl/ us/ˌʌn.rɪˈpiː.t̬ə.bəl/
(EVENTS)
[ usually before noun ]（事件、价格等）不可重复的，不会再有的
An unrepeatable event, price, etc. cannot happen again.
an unrepeatable offer/opportunity 不会再有的出价／机会
an unrepeatable experience 不可重复的经历
(WORDS)
（字眼或言语过于粗鲁或艰深而）不宜重提的，说不出口的
An unrepeatable word or remark used by another person is too rude or too difficult for you to repeat.
an unrepeatable joke/name 不堪重复的玩笑／说不出口的名字