holy war

noun
1.
a war waged for what is supposed or proclaimed to be a holy purpose, as the defense of faith.
2.
any disagreement or argument between fanatical proponents of radically differing beliefs, opinions, etc.:
a holy war on the merits of rival computer operating systems; a holy war about welfare reform.
Origin
1685-95
Examples from the web for holy war
  • There's almost no way to write about this subject without starting a holy war.
  • When it began last fall, it was the political equivalent of holy war.
British Dictionary definitions for holy war

holy war

noun
1.
a war waged in the cause of a religion