persistent aggressive behaviour directed towards a particular victim, particularly children at school, who cannot retaliate effectively
aggression deliberately and persistently directed against a particular target, or victim, typically one who is weak, vulnerable and defenseless aggression deliberately and persistently directed against a particular target, or victim, typically one who is weak, vulnerable and defenseless
is a specific type of aggression in which 1) the behaviour is intended to harm or disturb, 2) the behaviour occurs repeatedly over time, and 3) there is an imbalance of power, with a more powerful person or group attacking a less powerful one (Mayo Clinic, 2001)