Flyting is a really old type of insult poetry that people used to do in Norse and Celtic cultures. It was kind of like a verbal battle where two people would take turns insulting each other in really creative and rhyming ways. They might make fun of each other's appearance, intelligence, or just say really mean things to make the other person feel bad.
It was all done in good fun though, and wasn't meant to be taken too seriously. People would gather around and watch, and whoever had the best insults and rhymes would be declared the winner.
Nowadays, we don't really do flyting anymore, because it's not very nice to insult people like that. But some people still find it fascinating and like to study it to learn about the way people used to communicate in the past.