1. having to do something because it is your duty
   • ● I felt duty-bound to help him.
   • ● I felt in duty bound to report the incident.

[TahlilGaran] English Dictionary ▲

to be forced by duty or honor to do something
I was duty bound to talk to my friend about the money that I had lost.

[TahlilGaran] English Idioms Dictionary ▲

Abraham Lincoln walked miles once to return a few pennies that he had overcharged a woman because he felt duty bound to do it.

John felt duty bound to report that he had broken the window.

[TahlilGaran] English Idioms Dictionary ▲