promise vs swear

promise

verb
  • To commit to (some action or outcome), or to assure (a person) of such commitment; to make an oath or vow. 

  • To give grounds for expectation, especially of something good. 

noun
  • A transaction between two persons whereby the first person undertakes in the future to render some service or gift to the second person or devotes something valuable now and here to his use. 

  • A placeholder object representing the eventual result of an asynchronous operation. 

  • Reason to expect improvement or success; potential. 

  • an oath or affirmation; a vow 

swear

verb
  • To take an oath, to promise intensely, solemnly, and/or with legally binding effect. 

  • To promise intensely that something is true; to strongly assert. 

  • To take an oath that an assertion is true. 

  • To use offensive, profane, or obscene language. 

  • To be lazy; rest for a short while during working hours. 

  • To administer an oath to (a person). 

noun
  • A swear word. 

  • A lazy time; a short rest during working hours (especially field labour); a siesta. 

adj
  • Dull; lazy; slow. 

  • Top-heavy; too high. 

  • Reluctant; unwilling. 

  • Heavy. 

  • Niggardly. 

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