私交

zhè liǎng rén sù wú sī jiāo

这两人素无私交。

The two have never established a personal friendship.

wǒ de liǎng gè péng you sī jiāo hěn hǎo

我的两个朋友私交很好。

Two of my friends have been close friends.

wǒ hé bié rén méi yǒu sī jiāo

我和别人没有私交。

I am not personally acquainted with others.