勿 (w)

(wù) do not

勿忘国耻 (w)

(wùwàngguóchǐ) Never forget national humiliation, refers to Mukden railway incident of 18th September 1931 九一八事變|九一八事变 and subsequent Japanese annexation of Manchuria

勿忘我 (w)

(wùwàngwǒ) forget-me-not, genus Myosotis (botany)

勿替敬典 (w)

(wùtìjìngdiǎn) to continue to respect ancient canons (idiom)