How do you remove someone from "shared" under Finder?

I know that someone asked the same question a while ago and I did everything that was mentioned. I unchecked all the boxes under "system preferences > sharing" and that didn't work. I turned on my firewall and that didn't work either. It still says "John's MacBook Pro" under "shared. What else can I do to completely get rid of that? Also, what exactly does that mean? When I click on the name, it says "connecting" and then I get scared and x out lol.