inducement vs plugola

inducement

noun
  • An incentive that helps bring about a desired state. In some contexts, this can imply bribery. 

  • An introductory statement of facts or background information. 

  • The act of placing a port on a vessel's itinerary because the volume of cargo offered at that port justifies the cost of routing the vessel. 

plugola

noun
  • Undeclared or illicit publicity or product promotion, especially on radio or television. 

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