The acronym of "Not Even Funny, Bro." Commonly used by popular pussies on Facebook who are getting 5 billion chats at once so they type in only acronyms. Also used by trendy fat girls who think they're cool when they talk in 1337 and use acronyms 20 years later than everyone else.
K00l K4tzer - "I spilled ice cream on my socks, I'm fucking killing myself right now."
Fucking Faggot - ".....nefb.....n-e-f-b."