lifer vs rapist

lifer

noun
  • A prisoner sentenced to transportation for life. 

  • A person with a singular career path, especially in the military. 

  • A bird species seen for the first time by a birder who is keeping a list of all the species he or she has ever seen. 

  • A prisoner sentenced to life in prison. 

rapist

noun
  • A person who has committed rape. 

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