Explanation:

Unacceptable person

Persona non grata means unacceptable or unwelcome person. The maxim has evolved in the area of diplomatic relations which means that a foreign diplomat is unwelcome in that country. In other words, it is a status applied by a host country to foreign diplomats to remove their protection by diplomatic immunity from arrest and other normal kinds of
prosecution. Under Article 9 of the Vienna Convention on Diplomatic Relations, a receiving state may "at any time and without having to explain its decision" declare any member of a diplomatic staff persona non grata.[1] A person so declared is considered unacceptable and is usually recalled to his or her home nation. If not recalled, the receiving state "may refuse to recognize the person concerned as a member of the mission".