feedforward vs hang on

feedforward

verb
  • To respond in advance 

noun
  • An anticipatory response to expected changes in the environment of a system 

hang on

verb
  • To wait a moment. 

  • To hold, grasp, or grip. 

  • To pay close attention to, or regard with (possibly obsequious) admiration. 

  • To depend upon. 

  • To keep; to store something for someone. 

  • To continually believe in something; to have faith in. 

  • To persevere. 

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