operant vs relevant

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. 

relevant

adj
  • Directly related, connected, or pertinent, with important ramifications or implications. 

  • Related, connected, or pertinent to a topic. 

  • Not out of date; current. 

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