predecessor

详细解释:n. 前任, 先辈, 前身
【医】 初牙, 前辈, 祖先

英语解释：

名词 predecessor:

one who precedes you in time (as in holding a position or office)

例句：

He undid most of the good work of his predecessor.他把前任的大部分业绩毁掉了。