obligation

/ˌɑbləˈɡeɪʃən/
noun
  1. Something that you must do because of a law, rule, promise, or duty.
    • She felt a moral obligation to help her friend.
    • Citizens have an obligation to pay taxes.
    • The contract creates a legal obligation for both parties.
  2. A feeling of being grateful or indebted to someone because of something they have done for you.
    • I don't want to feel an obligation to return the favor.
    • You are under no obligation to buy anything.
    • He helped me out of a sense of obligation, not friendship.
Antonyms