involve vs restrain

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. 

restrain

verb
  • To strain again. 

  • To control or keep in check. 

  • To deprive of liberty. 

  • To restrict or limit. 

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