depressant vs hypnic

depressant

noun
  • A pharmacological substance which decreases neuronal or physiological activity. 

  • An agent that inhibits the flotation of a mineral or minerals. 

adj
  • reducing functional or nervous activity. 

hypnic

noun
  • Any sleep-inducing drug. 

adj
  • That induces sleep. 

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