obligation

/ˌɒblɪˈgeɪʃn ˌऑब्‌लिˈगेश्‌न्‌/ noun [C, U]

(an) obligation (to somebody) (to do something) the state of having to do something because it is a law or duty, or because you have promised क़ानूनी बाध्यता या कर्तव्य-भावना, या वचनबद्घता

The shop is under no obligation to give you your money back.

We have an obligation to help people who are in need.