incumbent

名词 incumbent:

1. the official who holds an office
   同义词：officeholder

形容词 incumbent:

1. lying or leaning on something else
2. necessary (for someone) as a duty or responsibility; morally binding
3. currently holding an office

1. It is incumbent upon justice to give some warnings of their doubt about a case.
   法官有责任提醒人们有关他们对案件的疑问。
2. It's incumbent on you to advise your son before he leaves home.
   在你儿子离家前给他忠告是你义不容辞的事。
3. The quality or condition of being incumbent.
   有义务负有义务的性质或状况

in.cum.bent

adj.（形容词）
Imposed as an obligation or a duty; obligatory:
有义务的：强加责任或任务的；有义务的：
例句：
felt it was incumbent on us all to help.
感到我们大家都来帮助是义不容辞的

Lying, leaning, or resting on something else:
凭依的，依靠的：躺、靠或放在其它物上的：
例句：
incumbent rock strata.
依附的岩石层

Currently holding a specified office:
在职的：当前任某一特定职位的：
例句：
the incumbent mayor.
在职的市长

n.（名词）
A person who holds an office or ecclesiastical benefice:
任职者：行政部门或教会中的任职者：
例句：
defeated the incumbent in a close election.
在一场势均力敌的选举中击败在职者

来源：
Middle English [holder of an office]
中古英语 [在职者]
from Medieval Latin incumbôns incumbent-
源自 中世纪拉丁语 incumbôns incumbent-
from Latin [present participle of] incumbere [to lean upon, apply oneself to]
源自 拉丁语 [] incumbere的现在分词 [靠在…上，致力于]
in- [on] * see in- 2
in- [在…上] *参见 in-2
-cumbere [to recline]
-cumbere [斜倚，向后靠]

【引伸】
incum.bently
adv.（副词）