Communication
Communication (from Latin commūnicāre, meaning "to share") is the act of conveying intended meanings from one entity or group to another through the use of mutually understood signs and semiotic rules.
Cooperation
Cooperation (sometimes written as co-operation) is the process of groups of organisms working or acting together for common, mutual, or some underlying benefit, as opposed to working in competition for selfish benefit. Many animal and plant species cooperate both with other members of their own species and with members of other species (symbiosis or mutualism).
Diplomacy
Diplomacy is the art and practice of conducting negotiations between representatives of states. It usually refers to international diplomacy, the conduct of international relations through the intercession of professional diplomats with regard to a full range of topical issues. International treaties are usually negotiated by diplomats prior to endorsement by national politicians. David Stevenson reports that by 1900 the term "diplomats" also covered diplomatic services, consular services and foreign ministry officials.
International
International mostly means something (a company, language, or organization) involving more than a single country. The term international as a word means involvement of, interaction between or encompassing more than one nation, or generally beyond national boundaries. For example, international law, which is applied by more than one country and usually everywhere on Earth, and international language which is a language spoken by residents of more than one country.
Diplomacy
Mr. Scott: Diplomats. The best diplomat I know is a fully activated phaser bank.
Star Trek: The Original Series A Taste of Armageddon (1966), teleplay by Gene L. Coon and Robert Hamner
Diplomacy
I'd like to think the best bunker buster is a diplomat.
Scott Ritter, in Chris Davis, "Scott Ritter Says Controversial Things About Clinton, Bush, Fox News, the Surge, etc.", Memphis Flyer (May 3, 2008).
Diplomacy
All diplomacy is a continuation of war by other means.
Zhou Enlai, Saturday Evening Post (27 March 1954); this is a play upon the famous maxim of Clausewitz: "War is the continuation of politics by other means".