operant vs operational

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. 

operational

adj
  • Functioning and ready for use. 

  • Effective or operative. 

  • Determined by means of practical measures. 

  • Of or relating to operations, especially military operations. 

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