functionality vs string to one's bow

functionality

noun
  • The ability to do a task, performance, or execution; a set of functions that something is able or equipped to perform. 

  • The presence of a functional group. 

  • In United States trademark law, the tendency of a product design to serve a function other than identification of the product, preventing that design from being protected as a trademark. 

string to one's bow

noun
  • A skill, ability or resource. 

  • A lover, paramour or suitor. 

How often have the words functionality and string to one's bow occurred in a corpus of books? (source: Google Ngram Viewer )