key up vs propel

key up

verb
  • To raise the intensity, excitement, tension, etc., of. 

  • To produce nervous tension in. 

  • To raise the pitch of. 

  • To raise (the whole ring of an arch) off its centering, by driving in the keystone forcibly. 

propel

verb
  • To provide an impetus for motion or physical action, to cause to move in a certain direction; to drive forward. 

  • To provide an impetus for non-physical change, to make to arrive to a certain situation or result. 

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