alderman vs envoy

alderman

noun
  • A member of a municipal legislative body in a city or town. 

  • A long pipe for smoking. 

  • A potbelly, paunch. 

envoy

noun
  • A representative. 

  • A messenger. 

  • A diplomat. 

  • A diplomatic agent of the second rank, next in status after an ambassador. 

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