a lasting (/deep-rooted/irreconcilable) hatred ❍ 过去互相怀有～的部落，如今友好相处。The clans who held a deep-rooted hatred for each other in the past live in harmony now.
九世之仇jiǔ shì zhī chóu
比喻积怨非常久远的仇恨。the national hatred is very far back but revenge, a lasting hatred