completion vs prepayment

completion

noun
  • The conclusion of an act of conveyancing concerning the sale of a property. 

  • The act or state of being or making something complete; conclusion, accomplishment. 

  • The space resulting from such an act. 

  • The act of making a metric space complete by adding points. 

  • A forward pass that is successfully caught by the intended receiver. 

prepayment

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

  • A payment in advance. 

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