operant vs purposeful

operant

adj
  • That operates to produce an effect. 

noun
  • Any of a class of behaviors that produce consequences by operating (i.e., acting) upon the environment. 

  • An operative person or thing. 

purposeful

adj
  • Having purpose; intentional. 

  • Having a purpose in mind; resolute; determined. 

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