bullying
The use of force or coercion to abuse or intimidate others. The behavior can be habitual and involve an imbalance of social or physical power. It can include verbal harassment or threat, physical or sexual assault or coercion and may be directed repeatedly towards particular victims, perhaps on grounds of race, religion, gender, sexuality, or ability. The victim of bullying is sometimes referred to as a "target".
Some methods of bullying include forcefully cutting hair, graffiti, humiliation, memorial on desk, simply punching/kicking the target, etc.