你死我活

nǐ sǐ wǒ huó

lit. you die, I live (idiom); irreconcilable adversaries

two parties cannot coexist

你

nǐ

you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)

死

sǐ

to die

我

wǒ

I; me; my

活

huó

to live