obligation
/ˌä-blə-ˈgā-shən/
noun
the action of obligating oneself to a course of action (as by a promise or vow)
something (such as a formal contract, a promise, or the demands of conscience or custom) that obligates one to a course of action
a debt security (such as a mortgage or corporate bond)
noun phrase
a feast on which Roman Catholics are duty-bound to attend mass
idiom
not required (to do something)
You are not under any obligation to stay.