In the Buff
At the same time, the word buff, itself, can also refer to ❛someone who is an expert on or a keen fan of a certain subject❜. The man in the comic is a film buff. This means that he either knows a lot about films or he is big fan of films - probably, he is both. There are many kinds of buff that one can be. For example, you could be a local history buff, a soccer buff or even an English idiom buff. What kind of buff are you?