The word "buff" can refer to a few different concepts depending on the context. Primarily, it means to shine or polish something, especially using a cloth or material that is soft. It can also refer to a person who is very enthusiastic or knowledgeable about a particular subject, especially in the context of hobbies or interests, like a "film buff." Additionally, in another context, "buff" can describe a strong, muscular physique.
The word "buff" has its roots in the use of a type of leather known as "buff leather," which is made from the hide of an animal. The term comes from the French word "buffe," meaning a buff coat, and it dates back to the 16th century. Its usage related to polishing surfaces began to evolve in the early 19th century, while the meaning associated with being an enthusiast emerged later.