retention vs riddance

retention

noun
  • The portion of a potential damange that must be paid for by the holder of an insurance policy. 

  • The act or power of remembering things 

  • The involuntary withholding of urine and faeces 

  • A memory; what is retained in the mind 

  • The length of time an individual remains in treatment 

  • The right to withhold a debt, or of retaining property until a debt due to the person claiming the right is duly paid; a lien. 

  • The act of retaining or something retained 

riddance

noun
  • The earth thrown up by a burrowing animal. 

  • The act of being rid of something; deliverance 

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