勿忘 is a classical, concise imperative phrase meaning 'do not forget' or 'never forget'. It combines the prohibitive particle 勿 (wù), which means 'do not' or 'must not', and the verb 忘 (wàng), meaning 'to forget'. Unlike modern colloquial alternatives like 别忘了 or 千万不要忘记, 勿忘 carries a solemn, literary, or even ceremonial tone—often seen in mottos, memorial inscriptions, slogans, and formal appeals. Its brevity and gravity make it especially common in contexts involving remembrance, duty, loyalty, or historical consciousness.

This phrase functions as a standalone command or appears at the end of sentences for rhetorical emphasis. While grammatically verb-like, it rarely takes objects directly in speech; instead, the thing to be remembered is usually implied or introduced separately (e.g., via context or a preceding clause). Learners should note that 勿忘 is not used in casual daily conversation—it would sound stiff or overly dramatic when reminding a friend to bring lunch.