One-word substitution (vocabulary): A continuing fight between parties, families, clans, etc. Choose the single best word that exactly matches the definition.

Given data

• Definition: a prolonged, often hereditary conflict between groups.

Reasoning through options
Feud — a long-standing and continuing conflict between families/clans/parties. Correct.Enmity — general hostility; not necessarily an ongoing series of hostilities.Quarrel — a dispute; can be brief.Skirmish — a brief fight; minor battle.

Final Answer
Feud