Diplomat Definition: An official representative of a state, present in another state for the purposes of general representation of the state-of-origin or for the purpose of specific international negotiations on behalf of the diplomat's state-of-origin. Related Terms: Ambassador, Persona Non Grata, Diplomatic Immunity, Diplomacy An official representative of a state, present in another state for the purposes of general representation of the state-of-origin or for the purpose of specific international negotiations on behalf of the diplomat's state-of-origin. They benefit from diplomatic immunity. Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!