joy killer vs opiate

joy killer

noun
  • killjoy (Someone or something that hinders fun.) 

opiate

noun
  • Something that dulls the senses and induces a false and unrealistic sense of contentment. 

  • A drug, hormone or other substance derived from or related to opium. 

verb
  • To treat with an opiate drug. 

adj
  • Soporific; inducing sleep or sedation. 

  • Relating to, resembling, or containing opium. 

  • Deadening; causing apathy or dullness. 

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