It can also be used as a noun, meaning "madwoman" or "fool".
Here are some examples:
* "Elle est folle." (She is crazy.)
* "C'est une folle idée." (It's a crazy idea.)
* "Il a agi comme un fou." (He acted like a fool.)
* "La folle du village." (The village madwoman.)
It's important to note that "folle" can be a strong word and should be used carefully, as it can be considered insulting.