means he's using his credit card to pay for membership in some sort of club connected to what he works/worked with, and to pay for his labour union. Labour unions are workers uniting to make themselves stronger against their employer.
Boris Becker's father, Karl-Heinz Becker, was an architect by profession.
He was a glover. Not really a profession, more of a trade.
fishing
He was a carpenter
efvwr
Quaid e Azam's father was a businessman by profession. He had leather factories in Karachi, Pakistan.
he is a barber
he was a lawyer.
He was a successful minister.
Elie's father's profession is business man, who takes care of his business as well as community.
He is house husband
He was an Art Teacher.