irruption vs sustenance

irruption

noun
  • An abrupt increase in the size of a movement or organization. 

  • An abrupt increase of an animal population. 

  • The action of irrupting or breaking into; a violent entry or invasion; an inbreaking; an intrusion. 

sustenance

noun
  • Something that provides support or nourishment. 

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