What's "anything but" mean and when's it used?

Native speaker’s answer
Rebecca
"Anything but" means "not at all!" It's usually used for emphasis. It indicates that something or someone is not at all something. It can also indicate that it'll be the opposite of that thing. Ex: It might not seem like it, but she's anything but shy. => not shy at all Ex: The hike will be anything but fun if he comes with. => it will be the opposite of fun, maybe terrible and boring.