何足挂齿

何足掛齒
hézúguàchǐ
  1. (humble) insignificant; not even worth mentioning
  2. insignificant; not even worth mentioning

Wiktionary

Entry Composition

1 何足 hézú
  1. (literary) why would it be worth; not worth
  2. why would it be worth; not worth
2 挂齿 guàchǐ to mention (e.g. "don't mention it")