That one person that everyone has on their friends list who has absolutely no idea how to correctly use facebook so they go around 'posting' and 'liking' like a complete ass.
Girl #1: OMG...TODAY JENIFER LIKED HER OWN STATUS!
Girl#2: OMMMMMGGG, SHE IS SOOO FBAWK.
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!