患难之交

huàn nàn zhī jiāo

a friend through hard times

Character by character

患huàn
trouble

难nàn
hardship

之zhī
's

交jiāo
friendship

我们是患难之交，他有事我一定帮。

We've been through hard times together; if he needs help, I'm there.

Tone: positive (praise).

难 is nàn (disaster). Opposite: 酒肉朋友, friends only for the good times.

Learn it in context

This idiom and thousands more are in Learn Chinese with Bao, with audio, pinyin and drills that make them stick.