Old greasy ugly nasty motherfuckers. Likes to lurk in dark corridors waiting to harass poor young women. These nasty sons of bitches are N-A-S-T-Y DISGUSTINGfat fucking mother fuckers.
Of any age in London England up to the end of the 20th century, a "lad" a person into petty crime maybe, also loud, bit of a Romeo with the ladies, tough street wise.
Possibly from "Guise" clothing/coverage/mask as in disguise. Often a street performer in "disguise".
or
Geezer from Yeezer/Yeeser from old Gaelic meaning Jesus.
"e's a bit of a geezer ain't e?"
"Yea, fuckin' well 'ard. But I reckon I could kick the fuck outta 'im".