explain vs overcome

explain

verb
  • To give a valid excuse for past behavior. 

  • To make plain, manifest, or intelligible; to clear of obscurity; to illustrate the meaning of. 

  • To make something plain or intelligible. 

overcome

verb
  • To recover from (a difficulty), to get over 

  • To surmount (a physical or abstract obstacle); to prevail over, to get the better of. 

  • To prevail. 

  • To win or prevail in some sort of battle, contest, etc. 

  • To come or pass over; to spread over. 

noun
  • The burden or recurring theme in a song. 

  • A surplus. 

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