oligarca

oligarca is masculine or feminine depending on context in Spanish.

oligarch (a member of an oligarchy)

“Grecia necesita reformas radicales que favorezcan a la sociedad y no a los oligarcas protegidos por los Gobierno anteriores.” — Greece needs radical reforms that favor society and not the oligarchs protected by previous governments.

Borrowed from Late Latin oligarcha, from Ancient Greek ὀλιγάρχης (oligárkhēs).