debtor vs defaulter

debtor

noun
  • One who owes another anything, or is under obligation, arising from express agreement, implication of law, or principles of natural justice, to pay money or to fulfill some other obligation; in bankruptcy or similar proceedings, the person who is the subject of the proceeding. 

  • A person or firm that owes money; one in debt; one who owes a debt. 

defaulter

noun
  • one who fails to fulfill an obligation or perform a task, especially a legal or financial one. 

How often have the words debtor and defaulter occurred in a corpus of books? (source: Google Ngram Viewer )