happy slapping

Từ điển Oxford Advanced Learner 8th

ˈhappy slapping 8 [happy slapping] BrE NAmE noun (BrE)uncountable
the practice of several people attacking sb while another person in the group makes a film of the attack
•A victim of happy slapping hit back at one of the attackers and broke her ribs.
•Schools banned camera phones because of the happy slapping craze.
•a happy slapping video