It is really interesting how many school administrators and parents alike become very frustrated when attempting to solve bullying issues. There are several sides to the argument. The victim claims the bully is humiliating/violating them. The school is not sure because they may not have a "clear definition" and therefore "need to investigate further" or do not have a "protocol". The bully claims he "is only joking."
The bully's parents might say the victim is over-sensitive about teasing.
At the end of the day, the definition need not be challenging. It really is simple.
If one child has asked another to stop a behavior, language or conversation and lets them know it is not acceptable by either getting upset or asking them to cease and they do not, on the second occasion, it becomes bullying. Period. Simple.
Every case is different and obviously, some are considerably less serious than others, but at the end of day,
the definition is solid. The consequences/punishment may change, but the definition does not.
The best way to stop a bully is to let him know, it is not acceptable to bully. Further, every child should let an adult know and that adult should use the above definition. From there, a bully should receive a learning consequence. Period. Simple.