Diplomacy refers to the management and negotiation of relationships between countries, typically carried out by their representatives or officials.
It also describes the ability to handle interactions with people in a tactful and sensitive way, avoiding conflict and misunderstanding.
"Diplomacy is the management of international relations and the art of managing people with skill and discretion."
Author’s summary: Diplomacy combines state-level negotiation with personal tact, requiring sensitivity, strategic thinking, and effective communication.