你死我活

nǐsǐwǒhuó
  1. lit. you die, I live (idiom); irreconcilable adversaries
  2. two parties cannot coexist

CEDICT

irreconcilable adversaries; two parties cannot coexist

Wiktionary

形容争斗得非常激烈。

重編國語辭典

Entry Composition

=1 你 nǐ you (informal, as opposed to courteous 您 nín)
=1 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.)
2 死 sǐ
  1. to die
  2. impassable
  3. uncrossable
  4. inflexible
  5. rigid
  6. extremely
  7. damned
3 我 wǒ
  1. I
  2. me
  3. my
4 活 huó
  1. to live
  2. alive
  3. living
  4. work
  5. workmanship