hypnic vs sleepy

hypnic

adj
  • That induces sleep. 

noun
  • Any sleep-inducing drug. 

sleepy

adj
  • Tending to induce sleep. 

  • Quiet; without bustle or activity. 

  • Tired; feeling the need for sleep. 

  • Suggesting tiredness. 

  • Dull; lazy. 

noun
  • The gum that builds up in the eye; sleep, gound. 

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