Collocations for diplomat - noun

chief, prominent, senior, top
Washington's top diplomat in Havana
the chief Cuban diplomat in the United States
two of the world's most prominent diplomats

consummate, distinguished, experienced, good, skilled
former, retired
foreign
career, professional
American, British, US, etc.
Western
a Western diplomat in Islamabad

be, serve as, work as
He served as a diplomat in Russia before the war.