machinal vs operative

machinal

adj
  • Of, or pertaining to machines. 

  • In the manner or style of a machine. 

operative

adj
  • Effectual or important. 

  • Functional, in working order. 

  • Having the power of acting; hence, exerting force, physical or moral; active in the production of effects. 

  • Producing the appropriate or designed effect; efficacious. 

  • Based upon, or consisting of, a surgical operation or operations. 

noun
  • An employee or other worker with some particular function or skill. 

  • A spy, secret agent, or detective. 

  • A participant in an operation. 

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