沒ㄇㄛˋ齒ㄔˇ不ㄅㄨˊ忘ㄨㄤˋmòchǐ‑búwàng

简没齿不忘
mòchǐ‑bùwàngㄇㄛˋ ㄔˇ ㄅㄨˋ ㄨㄤˋ

  1. 終身不會忘記。例 「您的救命之恩，我沒齒不忘」。

英lit. will not be forgotten even after one's teeth fall out, to remember as long as one lives, unforgettable (idiom)​