incumbent

现任者、在职者

The incumbent has a clear advantage in this year's election.

现任者在今年的选举中占有明显优势。

既有业者、现有厂商商业

New startups are challenging the incumbents in the banking sector.

新创公司正在挑战金融业的既有业者。

现任的、在职的

The incumbent mayor announced that she would seek a second term.

现任市长宣布她将争取连任。

有义务的、责无旁贷的正式，常用于 on/upon

It is incumbent upon all of us to protect these wetlands.

保护这些湿地是我们所有人的责任。