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1. of or concerning the profession, activity, or skill of managing international relations:

〖通例名詞の前で〗外交(上)の; 外交官の

e.g. diplomatic relations between the United States and Britain.

having or showing an ability to deal with people in a sensitive and effective way:

外交的手腕にすぐれた, 外交的な; «…に関して» 人扱いの上手な, 気が利く, 如才のない «about»

e.g. that was a very diplomatic way of putting it.

2. (of an edition or copy) exactly reproducing an original version:

古文書学の; 原文通りの

e.g. a diplomatic transcription.

early 18th century (in the sense ‘relating to official documents’): from modern Latin diplomaticus and French diplomatique, from Latin diploma (see diploma). diplomatic (sense 1) (late 18th century) is probably due to the publication of the Codex Juris Gentium Diplomaticus (1695), a collection of originals of important public documents, many of which dealt with international affairs.