1. To remove someone from your Livejournal, MySpace, Facebook, or other
social networking site. Doing this is often seen as a
passive-aggressive move, telling the person without telling them that you no longer want to be friends. It's also commonly a response to drama.
Defriending someone often causes more drama. There are sometimes valid reasons for doing this.
2. A sarcastic/joking reference to definition (1). Said to a friend who's being mildly irritating, joking that their behaviour would cause the speaker to 'take them off their friendlist'.
1. a) "Can you believe Amy
defriended me because I'm dating Chris? She only doesn't like him because he turned down her friend Nicole two years ago. How lame."
b) "Yeah, so I had to defriend Charlie. He kept
cluttering up my friendlist with stupid memes, and we haven't even communicated in a year. We'll probably never see each other again, so there's no point.
2. Julie: "I really like
Sawyer and Kate together on Lost!"
Sara: "Really? I prefer Jack and Kate, I don't really like Sawyer."
Julie, jokingly: "I can't believe you think that! Oh my god you are SO defriended!"