What term describes the intense rivalry developed after World War II between Communist and non-Communist nations?

The term that best describes the intense rivalry developed after World War II between Communist and non-Communist nations is "A Cold War." This period, lasting from roughly 1947 to 1991, was characterized by geopolitical tension, military competition, and ideological conflict primarily between the United States and its allies, representing capitalist democracies, and the Soviet Union with its allies, representing communist states.

The phrase "Cold War" effectively captures the nature of this conflict, as it was marked by a lack of direct military engagements between the superpowers, instead relying on indirect confrontations, espionage, propaganda, and proxy wars in other nations. The significant developments during this era included the arms race, the formation of military alliances such as NATO and the Warsaw Pact, and various conflicts in Asia, Africa, and Latin America where the two sides supported opposing factions.

The other terms do not accurately reflect the historical context or the global scale of the conflict. For instance, "Contention Period," "Feuding Era," and "Silent War" lack the recognition and specific historical references associated with the Cold War and do not encompass the complex political, military, and ideological dynamics that defined that era.