the.com/feud

means A bitter, long-running hostility between two people, families, or groups, kept alive over years through retaliation and resentment.

from Feud traces back to medieval Germanic law, where a related term described the state of deadly hostility between families, often tied to the right of vengeance for a killing — this sense merged with an Old French word, 'feide,' into Middle English. A separate word 'feud' meaning a fief or feudal estate comes from an entirely different root, related to 'fee' — pure coincidence that the two look identical, though it's tempting to imagine ancient landowners bickering over borders.