Truancy is a game mechanic in Bully.
If Jimmy fails to attend a class that he hasn't yet passed, he is considered truant. Authority figures will be on the lookout for him. If he is busted on campus by a Prefect or Faculty, he'll be taken directly to class. If he is busted by a Police officer or Orderly off-school grounds, he'll be dropped off at the front gates of the school by Officer Williams.
NPC students can also be busted for being truant. However, this rarely happens. Strangely, the Townies can also be busted for this offense despite the fact they do not attend Bullworth Academy.
Once Jimmy has passed a class, he can skip it without being considered truant. However, Jimmy will be sent to class if he gets busted at the academy.