piggy vs prisoner

piggy

noun
  • A toe. 

  • A pig, a greedy person. 

  • A member of the police. 

  • A pig (the animal). 

  • A guinea pig. 

adj
  • slovenly, dirty 

  • greedy 

prisoner

noun
  • Any person held against their will. 

  • A person who is or feels confined or trapped by a situation or a set of circumstances. 

  • A person incarcerated in a prison, while on trial or serving a sentence. 

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