In the U.K.: A guy, a bloke, a person in general.
The British equivalent of the American slang word "dude".
In the U.S.: An old man, particularly one who is either
cranky or
eccentric. Rather derogatory term.
(UK) "You're looking for Johnny? Yeah, he's that geezer over there in
the green coat."
(US) "Old man
Anderson keeps yelling at the kids playing outside. That geezer!"