deferment vs prepayment

deferment

noun
  • Officially sanctioned postponement of compulsory military service. 

  • An act or instance of deferring or putting off. 

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 deferment and prepayment occurred in a corpus of books? (source: Google Ngram Viewer )