'勿近' is a concise, formal command meaning 'do not approach' or 'keep away from.' The character 勿 (wù) is a classical negative particle meaning 'do not' or 'must not,' often used in prohibitions; 近 (jìn) means 'to approach,' 'to come near,' or 'close to.' Together, they form an imperative phrase emphasizing caution or danger — typically found on warning signs, safety instructions, or official notices rather than casual speech.

This phrase is commonly seen in contexts involving potential hazards: wild animals, hazardous materials, construction zones, or protected natural areas. Its tone is authoritative and urgent, reflecting seriousness and immediacy. While grammatically similar to modern Mandarin verbs like '别靠近' (bié kàojìn), '勿近' carries a more literary, official, or bureaucratic register — you’ll rarely hear it in conversation, but frequently see it printed on signs or in public announcements.