In pretty much every country around the world where drinking alcohol is a cultural norm, every single social circle includes at least one person who becomes "that guy" (plural: "those guys").

We all know of whom I speak: The one friend who makes himself stand out in all the wrong ways. He always gets absolutely trashed, and makes a COMPLETE tit out of himself.
"Yeah, my friend Dom just got chucked out of the union for getting his knob out in the middle of the dance floor before unloading his stomach onto the floor"

"Shit. Doesn't sound good".

"Standard. He can generally always be counted upon to be That Guy".
by Zarathustratosphere June 26, 2011
An actor whose face you recognize from other movies but whose name you don't know. Once That Guy's anme becomes known, he ceases to be That Guy. That Guy alums include Joe Pantaliano, Steve Buscemi, CLint howard, etc.
"Hey! That Guy!" (said while watching Out For Justice and the Mexican goon with the tattoo on his neck walks onscreen)
by Marcel Leroux August 17, 2004
Stereotypical middle-aged, balding, hawaiian-shirt wearing, IROC Camaro driving man with a beer gut, rose gradient sunglasses, and a trophy wife to whom he is 20 years her senior.
I hope I never end up like -that- guy.
by lord May 11, 2004
The guy driving down the road with his arm out of the window, holding a mattress to the top of his car.
by jahburbie December 8, 2005
1. The guy who is always the first person to be everywhere.
2. The guy who is always the first to point out something that everyone else is too shy to mention
3. The guy who simply tries to hard to fit in with the crowd.
1. Tyler was the first one at the party, he had to be that guy.
2. Well i didnt want to be that guy to point out that your fly was down.
3. Derek tried way to hard to impress us, hes just that guy.
by Green Machine 10 October 18, 2007
(N.)(that-guy)The guy who drives at night with those blue lights on his car AND his high beams on, but ONLY uses them when it's a perfectly clear night, and he shines them right into your bedroom just to wake you up before work. He does this multiple times a night just to make sure you don't go back to sleep.
He also drives behind people to make sure they can't see SHIT.
Boss: "Johnson, why are you late?!"
Johnson: "Yeah, you see, it was That Guy again...."
Boss: "Oh, don't sweat it then. That Guy's an asshole."

or

Guy 1 "Oh my fucking God, it's that guy again!"
Guy 2 "The black one? With the funny moustache?"
Guy 1 "No....."
Guy 2 "You mean the one with........ OH MY GOD! WHAT THE HELL IS THAT LIGHT?!"
Guy 1 " DON'T LOOK INTO THE LIGHT!"
Guy 2 " OH MY GOD, I CAN'T SEE, HOLY SHIT, I THINK WE'RE GONNA CRASH"
by Hady October 29, 2008