Hardcore punk is a type of music that is very fast, loud, and angry. It's like when you get so mad that you want to shout or hit something, but instead you listen to this music to feel better.
The people who play this music usually have guitars, basses, drums, and sometimes singers. They play really fast and sometimes the singing is more like shouting or screaming than singing.
The lyrics of hardcore punk are often about things that make people angry or upset, like politics, social issues, or people treating others badly.
When people go to see a hardcore punk band play, it's called a "show" and people usually dance or jump around a lot. This is called "moshing" and it can look like people are pushing each other, but they're actually just having fun and releasing their anger in a safe way.
People who like hardcore punk music often dress differently than other people, with things like leather jackets, ripped jeans, and sometimes they have tattoos or piercings. But it's important to remember that just because someone dresses differently or likes different music doesn't mean they're a bad person.