If something is pre-emptive, it is done before other people can act, especially to prevent them from doing something else.

The Treasury has decided to raise interest rates as a pre-emptive measure against inflation. 财政部决定加息，以此作为一项防止通货膨胀的预防性措施。

The prime minister authorized a pre-emptive air strike against the rebels. 首相批准了对叛乱分子进行空袭，先发制人。

We strongly oppose this misguided preemptive war.