inert vs spring fever

inert

noun
  • A substance that does not react chemically. 

verb
  • To fill with an inert gas to reduce the risk of explosion. 

adj
  • Unable to move or act; inanimate. 

  • Sluggish or lethargic. 

  • In chemistry, not readily reacting with other elements or compounds. 

  • Having no therapeutic action. 

spring fever

noun
  • A feeling of invigoration and restlessness associated with the arrival of the warm weather and renewal of nature in the spring season. 

  • A feeling of laziness or listlessness associated with the arrival of the warm, comfortable weather of the spring season. 

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