漢賊不兩立 [汉贼－两－]

Jyutping hon3 caak6 bat1 loeng5 laap6
Pinyin hàn zéi bù liǎng lì

Definitions (CC-CEDICT)
  1. lit. Shu Han 蜀漢|蜀汉[Shu3 Han4] and Cao Wei 曹魏[Cao2 Wei4] cannot coexist (idiom)
  2. fig. two enemies cannot live under the same sky
  3. (former KMT slogan against CCP) "gentlemen and thieves cannot coexist"
Definitions (Wiktionary)
  1. phrase, idiomatic, of two people or groups
    to be absolutely irreconcilable; to be enemies and not be able to coexist