微不足道

wēi bù zú dào

too small to mention

Character by character

微wēi
tiny

不bù
not

足zú
worth

道dào
mention

我做的这点儿事微不足道。

What I did is really nothing.

Tone: neutral.

A modest reply to thanks, or a put-down of someone else's contribution.

Learn it in context

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