hypnic vs hypnotic

hypnic

adj
  • That induces sleep. 

noun
  • Any sleep-inducing drug. 

hypnotic

adj
  • Inducing sleep; soporific. 

  • Of, or relating to hypnosis or hypnotism. 

noun
  • A person who is, or can be, hypnotized. 

  • A soporific substance. 

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