advisory vs extramural

advisory

adj
  • Containing advice; advising. 

  • Able to give advice. 

noun
  • A warning. 

extramural

adj
  • Describing teaching of students who are not resident at such an institution. 

  • Taking place outside the walls of an institution, especially a school or university. 

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