Depending on the context can be a way to point some out. Or used as a durogative. Or as a method of surprise
1. A phrase used to point out a guy in the room.
2. Used in conjunction with the word "oh" can be used as a durogative. A durogative meaning "oh God not him" or "Look guys, it's the guy we dislike, hate, find creep, we blame, find annoying, etc. Kinda like "oh" in the movie h@me.
3.a character in futurama.
"Oh that guy" said the crowd who were rolling there eyes as there "friend" approached .
Someone who talks too much and you want them to just shut up for once. This can apply to not just girls, but boys too.
Brian: Yo, that guy talks too much. Can't he just shut up already?
Joe: I dunno man, it seems like he just can't stop.
Why are you even reading this, you know your not that guy.
Look at jimmy over there, he’s not that guy.
The indistinct person who is the embodiment of all inconveniences. Used to alert someone that they're messing with your steaze.
That Guy: *takes headstart*
Other Person in race: Did you seriously just become that guy
A person who is not important enough for anyone to remember their name. That guy is most likely a loner or socially awkward.
Who the hell is that guy and why should I even care?