commission vs sign up

commission

verb
  • To put into active service. 

  • To send or officially charge someone or some group to do something. 

  • To place an order for (often a piece of art). 

noun
  • A fee charged by an agent or broker for carrying out a transaction. 

  • The thing to be done as agent for another. 

  • The act of committing (e.g. a crime or error). 

  • A sending or mission (to do or accomplish something). 

  • An official charge or authority to do something, often used of military officers. 

  • A body or group of people, officially tasked with carrying out a particular function. 

sign up

verb
  • To agree to purchase some good or service. 

  • To add one's own name to the list of people who are participating in something (including amateur, but not professional, teams) 

  • To add a name to the list of people who are participating in something. 

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