diplomatic

adj

1. Concerning the relationships between the governments of countries.

   “She spent thirty years working for Canada's diplomatic service.”

   “Albania immediately severed diplomatic relations with Zimbabwe.”

   “Born in 1950 towards the end of the Stalin era to diplomatic parents, he was educated at the elite Russian Institute of International Relations before ascending to become Russia’s envoy at the UN, where for a decade he lived through the trauma of the collapse of the Soviet Union.”

2. Exhibiting diplomacy; exercising tact or courtesy; using discussion to avoid hard feelings, fights or arguments.

   “Thoughtful corrections can be diplomatic as well as instructional.”

3. Describing a publication of a text which follows a single basic manuscript, but with variants in other manuscripts noted in the critical apparatus.
4. Relating to diplomatics, or the study of old texts; paleographic.

noun

1. (uncountable)The science of diplomas, or the art of deciphering ancient writings and determining their age, authenticity, etc.; paleography.

   “In its broadest aspect, the subject-matter of diplomatic is the relation between documents and facts.”