不足挂齿

bù zú guà chǐ

not worth mentioning (reply to thanks)

Character by character

不bù
not

足zú
worth

挂guà
hang on

齿chǐ
teeth

这点小事不足挂齿，你别放在心上。

It was nothing, really. Don't give it another thought.

Tone: neutral.

More formal than 不客气; also 何足挂齿.

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