‘难忘’ (nán wàng) is an adjective meaning 'unforgettable' — literally 'difficult to forget'. The first character 难 (nán) means 'difficult' or 'hard', and the second character 忘 (wàng) means 'to forget'. Together, they form a compound that emphasizes the emotional weight or vividness of an experience that resists fading from memory. It’s commonly used to describe moments, people, places, or feelings that leave a lasting impression — often positive, though it can occasionally carry bittersweet or painful connotations depending on context.

This word appears frequently in storytelling, personal reflections, travel writing, and sentimental expressions. It typically modifies nouns directly (e.g., 难忘的经历 — 'an unforgettable experience') or follows copulas like 是 or 真 (e.g., 这真是一次难忘的旅行). Unlike some adjectives, it rarely stands alone as a predicate without supporting structure — it usually needs a noun or descriptive phrase to anchor its meaning.