1. A person who for all intents and purposes cannot possibly hope to be superior to any one person in any field.
2. Someone who makes every mistake possible, throws countless interceptions, drives like an incredible crash dummy, and gets into relationships with girls who have kids.
3. See jerk-off.
"Hey Mike is a real Cheedums"
"What makes you think that?"
"He makes decisions like a retarded baby."
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!