A war in which major powers support opposing sides without directly fighting each other is called:

The correct answer is Proxy War. A proxy war is a conflict where two major powers or states use third parties (or proxies) to fight on their behalf instead of directly engaging each other. Classic examples include the Vietnam War (US vs USSR via North/South Vietnam) and the Cold War proxy conflicts. Among the options:

• Cold War: This is a period of geopolitical tension, not a type of war.
• Civil War: A war within a single country.
• Proxy War: Correct; major powers support opposing sides without direct involvement.
• Guerrilla War: A type of irregular warfare, not defined by outside support.

Thus, the correct term is "Proxy War".