萍水相逢

píng shuǐ xiāng féng

to meet by chance as strangers

Character by character

萍píng
duckweed

水shuǐ
water

相xiāng
each other

逢féng
meet

我们萍水相逢，他却帮了我很大的忙。

We'd only just met by chance, yet he helped me enormously.

Tone: neutral.

Like duckweed drifting together on the water.

Learn it in context

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