狗嘴裏吐不出象牙 [－－里－－－－－]

Jyutping gau2 zeoi2 leoi5 tou3 bat1 ceot1 zoeng6 ngaa4
Pinyin gǒu zuǐ li tǔ bù chū xiàng yá

Definitions (CC-CEDICT)
  1. lit. no ivory comes from the mouth of a dog (idiom)
  2. fig. one does not expect fine words from a scoundrel