clarify vs involve

clarify

verb
  • To make clear or bright by freeing from feculent matter. 

  • To grow clear or bright; to clear up. 

  • To make clear or easily understood; to explain in order to remove doubt or obscurity. 

  • To grow or become clear or transparent; to become free from feculent impurities, as wine or other liquid under clarification. 

involve

verb
  • To complicate or make intricate. 

  • To take in; to gather in; to mingle, blend or merge. 

  • To cause or engage (someone or something) to participate or to become connected or implicated. 

  • To comprise or include; to have as a related part. 

  • To envelop, enfold, entangle. 

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