irrevocable

a. 不能唤回的,不能取消的,不能变更的

I am sorry to say the only term of payment we can accept is100% irrevocable documentary letter of credit.

抱歉地说，我们能接受的付款条件只有100％不可撤销跟单信用证。

The decision has been made and is irrevocable.

木已成舟已作出决定，无法反悔