The phrase "rugged charm" is an idiomatic expression that refers to the attractive quality of something or someone that is unpolished, imperfect and has a certain raw appeal. It suggests that the object or person in question has a unique character and authenticity that is appealing despite any flaws or imperfections. The phrase can be used to describe a variety of things, such as an old building with a rustic beauty, a person who is charming despite their rough edges, or a natural landscape with rugged beauty.