in im (instant messaging) a griefer might keep sending spam messages to someone, knowing the messages will overload the other person's computer
an individual who uses online games, instant messaging, e-mail, or any other communication method to harass, obstruct, or in some way make an experience sour for another person
"in im (instant messaging) a griefer might keep sending spam messages to someone, knowing the messages will overload the other person's computer" What is the definition of "griefer"?