don vs mentor

don

noun
  • A university professor, particularly one at Oxford or Cambridge. 

  • An employee of a university residence who lives among the student residents. 

  • A mafia boss. 

  • Any man, bloke, dude. 

verb
  • To put on clothing; to dress (oneself) in an article of personal attire. 

mentor

noun
  • A wise and trusted counselor or teacher. 

verb
  • To act as someone's mentor. 

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