stimulus vs tranquilizer

stimulus

noun
  • A sting on the body of a plant or insect. 

  • Something external that elicits or influences a physiological or psychological activity or response, or that affects any of the sensory apparatuses. 

  • An external phenomenon that has an influence on a system, by triggering or modifying an internal phenomenon; for example, a spur or incentive that drives a person to take action or change behaviour. 

tranquilizer

noun
  • That which tranquillizes or soothes. 

  • A drug used to reduce anxiety or tension. 

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