( old-fashioned , BrE , informal ) used by older men of the middle and upper classes as a friendly way of addressing another man
OLD BOY, CHAP, MAN, ETC.
Meaning of OLD BOY, CHAP, MAN, ETC. in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005