What does "holy war" mean?

A war which is primarily caused or justified by differences in religion and beliefs.

What is a synonym for "holy war"?

Common synonyms include: armageddon, brushfire war, campaign, civil war, crusade, crusades.

noun

noun ·Rare ·Advanced level

Noun

1
A war which is primarily caused or justified by differences in religion and beliefs.
"The conflict is beginning to look like a holy war between Sunnis and Shias."
2
A long-running and acrimonious debate or flame war over personal preferences in technical matters, such as the choice between little-endian and big-endian representation. Internet
3
The rivalry between the sports teams of Brigham Young University and the University of Utah.

"The conflict is beginning to look like a holy war between Sunnis and Shias."