请生成一些俚语及其定义。
1. "Don't be a square" - don't be boring or uncool
2. "Kick the bucket" - to die
3. "Ace" - to be excellent or skilled
4. "Bummed out" - to be sad or depressed
5. "Chill out" - to relax or calm down
6. "Couch potato" - someone who spends a lot of time sitting and watching TV
7. "Freak out" - to become extremely upset or frightened
8. "Hang loose" - to relax and take it easy
9. "Hit the road" - to leave or start a journey
10. "Screwed up" - to have made a mistake or messed something up.