Definitions

1. adjective

relating to or involving the conduct or relations between nations, governments, or international organizations, especially in a way that is skillful, tactful, or courteous

“The diplomatic efforts of the envoy helped to ease tensions between the two countries.”

2. noun

a person skilled in the conduct of foreign affairs, especially a person appointed to represent a country at a conference or in negotiations

“The ambassador was a skilled diplomat who helped to negotiate a peace treaty.”