Learner's definition of OBLIGATION
1 : something that you must do because of a law, rule, promise, etc.
The firm must fulfill its obligations under the contract. = The firm must fulfill its contractual obligations.
Both landlord and tenant should know their rights and obligations. [=responsibilities]
You can try the machine for free without obligation. [=without being required to buy it or to do anything else]
You are not under any obligation to stay. [=you are not required to stay]
You're under no (legal) obligation to return the money. [=there is no law that requires you to return the money; you do not have to return the money]
2 : something that you must do because it is morally right
She believes that all people have a moral obligation to defend human rights.
He argues that people in a community have certain obligations to each other.
She failed to fulfill her obligations as a parent.