Noun
1. the waging of armed conflict against an enemy;
"thousands of people were killed in the war"2. a legal state created by a declaration of war and ended by official declaration during which the international rules of war apply;
"war was declared in November but actual fighting did not begin until the following spring"3. an active struggle between competing entities;
"a price war""a war of wits""diplomatic warfare"4. a concerted campaign to end something that is injurious;
"the war on poverty""the war against crime"