For purposes of this Division: Course of conduct means a persistent pattern of conduct, composed of two or more acts over a period of time, however short, that evidences a continuity of purpose. Course of conduct does not include constitutionally protected activity. Credible threat means an expressed or implied threat against the life of another person or to cause bodily injury to another person which is made with the intent and the apparent ability to carry out the threat so as to cause the person who is the target of the threat to reasonably fear for his or her safety or for the safety of another person or to suffer substantial emotional distress. Harass means to engage in a knowing and willful course of conduct directed at a specific person which serves no legitimate purpose and which would seriously alarm, annoy, or intimidate the person. The course of conduct must be such as would cause a reasonable person to suffer substantial emotional distress. Stalk means to engage in an intentional course of conduct directed at a specific person which serves no legitimate purpose and which would seriously alarm, annoy, intimidate, or harass the person. The course of conduct must be such as would cause a reasonable person to suffer substantial emotional distress.