sedative vs somnific

sedative

adj
  • Calming, soothing, inducing sleep, tranquilizing 

noun
  • An agent or drug that sedates, having a calming or soothing effect, or inducing sleep. 

somnific

adj
  • Causing sleep; somniferous. 

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