helotism vs proscription

helotism

noun
  • The permanent oppression of a nominally free group of people 

  • A form of mutualism in which one species is forced to perform tasks for another, for their mutual benefit 

proscription

noun
  • A prohibition. 

  • Decree of condemnation toward one or more persons, especially in the Roman antiquity. 

  • A decree or law that prohibits. 

  • The act of proscribing, or its result. 

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