When a friend goes behind your back and goes with your ex. It's such a scatheaded thing to do. It's an un-written rule between friends, to never go near eachothers ex's.
Oh they are such scatheads, she went behind my back and got with my ex, what a bitch!
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!