preferment vs prepayment

preferment

noun
  • Prior claim (on payment, or on purchasing something); the first rights to obtain a particular payment or product. 

  • Advancement to a higher position or office; promotion. 

  • A position (especially in the Church of England) that provides profit or prestige. 

  • A mixture of flour, water and yeast that is allowed to ferment prior to another baking process 

prepayment

noun
  • A payment in advance. 

  • An asset recognized in respect an expense incurred in a period for which the benefit will be received in a future period. 

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