jaffy vs postgraduate

jaffy

noun
  • A person in their first year at an institution, primarily a university. 

postgraduate

noun
  • A person continuing to study in a field after having successfully completed a degree course. 

adj
  • Of studies which take place after having successfully completed a degree course. 

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