These characters combine to literally mean “name/reputation not emptily spread.” The idea is that the fame or renown that has been passed around among people is solid and true, not just a hollow rumor. It's a reputation backed by substance.
In Chinese culture, one's 名 (míng), or name/reputation, is incredibly important. It represents a person's honor, legacy, and social standing. Building a good name is a lifelong endeavor, and having one's reputation validated is a great source of pride. The idiom 名不虚传 taps directly into this cultural value. To say that someone or something is `名不虚传` is to bestow a high form of respect, affirming that their public image is authentic and their achievements are real. A Western parallel is the phrase “to live up to the hype,” but there's a subtle difference. “Hype” can sometimes feel temporary or media-driven. 名不虚传, on the other hand, often implies a reputation built more organically over time through word-of-mouth (`口碑 kǒubēi`) and consistent quality. It speaks to a legacy, not just a fleeting trend. Praising an old master painter or a century-old restaurant with this phrase feels more fitting than using it for the latest smartphone that's been heavily marketed.
名不虚传 is a common and highly positive idiom used in both spoken and written Chinese. It's not overly formal but carries a sense of sincere admiration.
It's almost always used after you have personally verified the reputation. It's the “Aha!” moment of confirmation.