Obligation

n.
  1. The act of obligating.
  2. That which obligates or constrains; the binding power of a promise, contract, oath, or vow, or of law; that which constitutes legal or moral duty.
  3. Any act by which a person becomes bound to do something to or for another, or to forbear something; external duties imposed by law, promise, or contract, by the relations of society, or by courtesy, kindness, etc.
  4. The state of being obligated or bound; the state of being indebted for an act of favor or kindness; -- often used with under to indicate being in that state; as, to place others under obligations to one.
  5. (Law) A bond with a condition annexed, and a penalty for nonfulfillment. In a larger sense, it is an acknowledgment of a duty to pay a certain sum or do a certain things.
    6. Days of obligation .
    See under Day.
    under obligation, under an obligation .
    in a state of obligation{4}.