The definition of "cheat" is "to act unfairly or dishonestly in order to gain an advantage, especially in a game or examination."
As far as I know, Reggie Bush didn't do anything to gain an advantage competitively, so I'm curious what you mean by this. Did he break NCAA rules at the time? Yes. Did he cheat to win his Heisman or gain a competitive advantage on the football field? No. In fact, according to the definition, I don't think he "cheated" at all.