Defriendization 

A large-scale deletion of friends from a social networking site. Similar to deforestation, it can have drastic effects on the remaining landscape of your friends list. The people you unfriend may then Facebook chat rape or Facebook stalk your mutual friends, asking why you've cleared an entire forest of people.

"I had to do some serious defriendization on FB after I dumped my stupid ho. No big deal, I hate her skanky, retarded friends anyway. Sorry if they come after you asking what happened, just tell them to get stuffed."

Defriendization by Rubenonfire February 6, 2010

Defriendinition

submitting, in some form, your friend's name as a definition on Urban Dictionary

Inundated by defriendinitions, it is understandable that occasionally a few get by the editors.

Defriendinition by Takkislacky January 31, 2010

defriendation 

The mass defriending of people on Facebook as a result of said people's actions in real life

Because of their excessive pretentiousness, defriendation has become a norm within my social group.

defriendation by Keifer41170 March 22, 2014