inert vs unmotivated

inert

adj
  • Unable to move or act; inanimate. 

  • Sluggish or lethargic. 

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

  • Having no therapeutic action. 

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

noun
  • A substance that does not react chemically. 

unmotivated

adj
  • Lacking motivation, without impetus to strive or excel. 

  • For which there is no motive. 

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