bounden

形容词 bounden:

1. morally obligatory

1. It's not a case of whether Enid wants to give evidence or not. If she overheard a criminal conversation, it's her bounden duty to report it to the police.
   现在的问题不是伊妮德是否愿意作证。假如她偶然听到罪犯的谈话，那么，向警方报告是她义不容辞的责任。

bound.en

adj.（形容词）
Obligatory:
有义务的：
例句：
their bounden duty.
他们应尽的义务

Archaic Being under obligation; obliged.
【古语】 有义务的；应当的

来源：
Middle English [past participle of] binden [to bind]
中古英语 [] binden的过去分词 [约束]
from Old English bindan * see bind
源自 古英语 bindan *参见 bind