Definition of war:
a conflict involving the organized use of arms and physical force between countries or other large-scale armed groups. The warring parties hold territory, which they can win or lose; and each has a leading person or organization which can surrender, or collapse, thus ending the war; a campaign against something. E.g., the war on drugs is a campaign against the use of narcotic drugs; the war on terror is a campaign against terrorist crime
to engage in conflict with a foe
"his emotions war with his intellect, making him conflicted."