Harassment covers a wide range of behaviors of an offensive nature. It is commonly understood as behavior that demeans, humiliates, and intimidates a person. In the legal sense, these are behaviors that are disturbing, upsetting, or threatening to a person. Some harassment evolves from discriminatory grounds, and has the effect of nullifying a person's rights or impairing a person from utilising their rights.

When harassing behaviors become repetitive, it is defined as bullying. The continuity or repetitiveness and the aspect of distressing, alarming or threatening may distinguish it from insult. It also constitutes a tactic of coercive control, which may be deployed by an abuser. Harassment is a specific form of discrimination, and occurs when a person is the victim of unwanted intimidating, offensive, or humiliating behavior.

In some jurisdictions, to qualify as harassment, there must be a connection between the harassing behavior and a person's protected personal characteristics or prohibited grounds of discrimination, but this is not always the case. Although harassment typically involves behavior that persists, serious and malicious one-off incidents are also considered harassment in some cases.