Learner's definition of GUY
1 [count] : a man
He seems like a nice guy.
Who's that guy she's with?
It's hard to tell the good guys [=the heroes] from the bad guys [=the villains] in this movie.
2 guys [plural], chiefly US — used to refer to two or more people
Quiet down, guys—I'm trying to get some sleep here!
You guys [=you both/all] should come visit us sometime.
Would you guys like anything else?