1. The state of owing something (especially money); "he is badly in debt".[Wordnet]
2. Money or goods or services owed by one person to another.[Wordnet]
3. An obligation to pay or do something.[Wordnet]
4. That which is due from one person to another, whether money, goods, or services; that which one person is bound to pay to another, or to perform for his benefit; thing owed; obligation; liability.[Websters]
5. A duty neglected or violated; a fault; a sin; a trespass.[Websters]
6. An action at law to recover a certain specified sum of money alleged to be due.[Websters].