Zealotry

Etymology

From "Zealot," from Greek "zēlōtēs" (an ardent follower), from "zēlos" (zeal). The original Zealots were a first-century Jewish faction that resisted Roman rule by force; their name became a general term for fierce, intolerant devotion.

noun · /ZEL-uh-tree/
Uncompromising, militant devotion to a cause or belief.
What it names
Names conviction turned combative — the temperament that treats disagreement as enmity.
Example
The reform movement’s zealotry alienated the very moderates it needed to win.
Related idea
Fanaticism names the frenzied intensity of belief; zealotry names its aggressive, crusading activity. The fanatic burns inwardly; the zealot marches.