ultimatum

1. N-COUNT An ultimatum is a warning to someone that unless they act in a particular way, action will be taken against them. 最後通牒

They issued an ultimatum to the police to rid the area of racist attackers, or they will take the law into their own hands. 他們曏警方發出了最後通牒，要他們清除掉該地區的種族主義襲擊者，否則他們就要自行採取行動。