Cyberbullying is bullying carried out online: repeated messages meant to hurt, humiliating posts or pictures, impersonation, and deliberate exclusion from group chats. What separates it from an argument is repetition and an imbalance of power — one person, or a group, singling somebody out.
Group chats are where much of it happens among school-age children, because a group can pile on and a screenshot can travel.
What helps: blocking and muting, leaving a group, keeping screenshots, reporting the account, and telling a trusted adult. Schools in many places have their own policies that cover bullying outside school hours.
Where Naven stands
Harassment and bullying is one of the twelve categories screened before a message is delivered, and serious refusals on three different days within 30 lead to a pause or a suspension. Naven deliberately does not screen ordinary insults or arguments, so a disagreement between friends is delivered. Anybody can block or report from a conversation's menu without asking anybody else.