debtor vs parasite

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. 

parasite

noun
  • A person who lives on other people's efforts or expense and gives little or nothing back. 

  • A sycophant or hanger-on. 

  • An organism that lives on or in another organism of a different species, deriving benefit from living on or in that other organism, while not contributing towards that other organism sufficiently to cover the cost to that other organism. 

  • A climbing plant which is supported by a wall, trellis etc. 

  • A retainer or companion of an ancient Celtic warrior, who praised him in song or poetry at gatherings; a bard. 

  • A component of a composite aircraft which is carried aloft and air-launched by a larger carrier aircraft or mother ship to support the primary mission of the carrier. 

  • Lice, fleas, ticks and mites are widely spread parasites. 

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