A teenage male who is a wannabe "skater", although does not posses any skateboarding skills but dresses like a "skater" nonetheless. A "Poser Skater". Usually these males are between 11-15, after which they grow out of this phase. The telltale sign of a Sk8erBoi is that he is never actually skating on his board, but always carrying it with him.
Did you see John this month?
He's a Sk8erBoi now, he used to be an Emo, but that didn't work out for him.
A young teenage male WALKING down the street with his board tucked under his arm.