discern vs grasp

discern

verb
  • To perceive differences. 

  • To distinguish something as being different from something else; to differentiate. 

  • To perceive, recognize, or comprehend with the mind; to descry. 

  • To detect with the senses, especially with the eyes. 

grasp

verb
  • To understand. 

  • To take advantage of something, to seize, to jump at a chance. 

  • To grip; to take hold, particularly with the hand. 

noun
  • Understanding. 

  • That which is accessible; that which is within one's reach or ability. 

  • Grip. 

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