obligation

noun5

1. •
   A social, legal, or moral requirement, duty, contract, or promise that compels someone to follow or avoid a particular course of action.

   • I feel I'm under obligation to attend my sister's wedding, even though we have a very frosty relationship.
2. •
   A course of action imposed by society, law, or conscience by which someone is bound or restricted.
3. •
   A legal agreement stipulating a specified action or forbearance by a party to the agreement; the document containing such agreement.
4. •
   Reason for being obliged to, that is, grateful for, something.
5. •
   The act of binding oneself by a social, legal, or moral tie to someone.