TFU, an abbreviation which stands for "The Fuckest Uppest", is generally used to describe something which is dangerous due to a capacity for violent unpredictability. It suggests something which is "the most fucked-up" in the sense of being the most unstable, irrational, erratic, easily provoked or insane with anger, and therefore something not to be messed with.

The term first came into popular usage in the BBC comedy programme 'Spaced' (Simon Pegg's character paints the letters on his battle robot in order to make it more intimidating). Apparently TFU is the graffiti signature of one of the members of the Spaced crew.
ED-409 from Robocop is TFU. Compared to him the Terminator is like a special needs child with a silly haircut.
by Megastar July 9, 2006
The Final Upset- A band based out of Orange County CA formed in 2012
TFU is The Final Upset.
by TFU,T.F.U,T.Fu,tfu,Tfi,tfy January 17, 2013
"you can't freeload off my booze anymore"
"TFU Bitch!"
by emo October 6, 2004
T.F.U. Too fucked up... When you go out and get too wasted and do some fucked up shit or black out and not remember any of it.. You text it to your friends After a crazy night because you did some crazy shit.
What happened to you last night?
I passed out in the Steak n Shake drive thru and a cop had to take me home. I was too tfu.

When going to SIUC for the weekend you know you are going to get too fucked up

Text:TFU last night FMP(Fuck my pussy)
Dude, I know I was TFU too
by maynard87 September 8, 2012
Fuckups or a Team of fuckups , TEAMFUCKUP a member of this team does not choose this fact they just are a fuckup, you can then use it to relate to all day to day matters rub a little tfu on it and hey presto it all goes to shit haha its not all bad sometimes good things happen but in really fucked up ways!

Copyright Amazing Dunny & Lawdawg (master fuckups)
Been thinking of an example for a year now cant even do that
Thats TFU Baby!
by Matthew Lawson April 5, 2007
Girl: I see to many tfu's
Boy: You have buttsex with to many tfu's
Girl: Nah that's all you
by Ohgeeeeeeeeez July 24, 2010