depressant vs soporific

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. 

soporific

noun
  • Something inducing sleep, especially a drug. 

  • Something boring or dull. 

adj
  • Boring, dull. 

  • Tending to induce sleep. 

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