strike off vs undersell

strike off

verb
  • To erase from an account; to deduct. 

  • To separate by a blow. 

  • To remove from a list or register. 

  • To print. 

undersell

verb
  • To sell something for less than its value. 

  • To sell goods for a lower price than a competitor. 

  • To put forward an idea, or to market a new product, with insufficient enthusiasm. 

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