promising vs promissory

promising

adj
  • Showing promise, and likely to develop in a desirable fashion. 

  • a promising young apprentice 

  • Encouraging and inspiring confidence. 

noun
  • The act of making a promise. 

promissory

adj
  • Containing or consisting of a promise. 

  • Stipulating the future actions required of the parties to an insurance policy or other business agreement. 

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