exempt vs grandfather

exempt

verb
  • To grant (someone) freedom or immunity from. 

noun
  • One of four officers of the Yeomen of the Royal Guard, having the rank of corporal; an exon. 

  • One who has been released from something. 

  • A type of French police officer. 

adj
  • Free from a duty or obligation. 

  • Not entitled to overtime pay when working overtime. 

grandfather

verb
  • To retain discontinued laws or rules for (a thing, person or organization previously affected by them). 

  • To be, or act as, a grandfather to. 

noun
  • A father of someone's parent. 

  • A male forefather. 

  • The archived older version of a file that immediately preceded the father file. 

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