behoove vs impel

behoove

verb
  • To befit, be appropriate or necessary to somebody. Alternative form of behove. 

  • To be fitting. 

impel

verb
  • To urge a person; to press on; to incite to action or motion via intrinsic motivation. 

  • To drive forward; to propel an object, to provide an impetus for motion or action. 

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