careful vs operant

careful

adj
  • Taking care; attentive to potential danger, error or harm; cautious. 

  • Conscientious and painstaking; meticulous. 

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. 

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