[noun] [C] [dated] [formal] - a person who has the authority to act as the representative of his or her country, esp. in another countryAmbassadors and plenipotentiaries bowed low as the Emperor and Empress entered.
PLENIPOTENTIARY
Meaning of PLENIPOTENTIARY in English
Cambridge English vocab. Кембриджский английский словарь. 2012