complicate vs explain

complicate

verb
  • To make complex; to modify so as to make something intricate or difficult. 

  • To involve in a convoluted matter. 

explain

verb
  • To make something plain or intelligible. 

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

  • To give a valid excuse for past behavior. 

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