‘宿敌’ literally combines ‘宿’ (sù), meaning ‘long-standing’ or ‘deep-rooted’, and ‘敌’ (dí), meaning ‘enemy’ or ‘rival’. Together, they form a noun meaning ‘archrival’ — someone or something with whom one has had a prolonged, intense, and often personal rivalry. Unlike ordinary rivals, a 宿敌 implies history, repeated confrontation, and deep mutual antagonism.

This term is commonly used in storytelling, sports commentary, wildlife documentaries, and historical narratives. In animal contexts, it often describes species locked in enduring ecological competition — for example, lions and hyenas competing for prey and territory across generations. It carries a slightly literary or dramatic tone and is rarely used in casual daily speech about minor disagreements.