involutional vs involved

involutional

adj
  • characterized by involution 

  • of or pertaining to involution 

involved

adj
  • Complicated. 

  • Having an affair with someone. 

  • Associated with others, be a participant or make someone be a participant (in a crime, process, etc.) 

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