look up any word, like donkey punch:
 
15.
As of August 13th, 2009: International Suit Up Day.

STFU stands for "Suit the fuck up." It should be said when someone is not legendary (i.e not wearing a suit.) Should be said to anyone not wearing a suit on International Suit Up Day.
Person A (Wearing a suit) walks up to Person B (not wearing a suit)

Person A: "Dude STFU"
by Syko/Aran August 13, 2009
 
16.
Shut The Fuck Up.

An acronym that will get you reported and punished in World of Warcraft, because Blizzard is fascist.
Nub Rogue in BG chat: OMGWTF YOU GUYS SUCK!
Annoyed Player: Dude, stfu and play.
by koalaroo February 29, 2008
 
17.
shut the fuck up

I said STFU You Ass-Rammers.
by mebhoopz September 30, 2006
 
18.
What you tell your boss when he asks the same damn question that you have answered at least 10 times that day!
read the damn memo and STFU Rob!
by The Angry Worker Ant April 14, 2009
 
19.
The submission finishing move of John Cena. This hold is known in professional wrestling as the Stepover Toehold Sleeper (STS) and innovated by Masahiro Chono. The wrestler performs a stepover toehold and wraps his arm around the neck of the opponent as in a sleeper hold.
John Cena made Batista tap out when he applied the STFU.
by RGI May 14, 2007
 
20.
Shut the fuck up.

Or, if you're in AP U.S. history, the Southern Tenant Farmers Union.
The AAA told the STFU to STFU
by bishthemighty February 20, 2011
 
21.
Southern Tenant Farmers Union. Formed in response to FDR's agricultural policies during the Great Depression.
We learned about the STFU today in history class.
by Richard Swett June 13, 2010