pure vs rarefied

pure

adj
  • Free of immoral behavior or qualities; clean. 

  • Of a single, simple sound or tone; said of some vowels and the unaspirated consonants. 

  • Free of foreign material or pollutants. 

  • Free of flaws or imperfections; unsullied. 

  • Done for its own sake instead of serving another branch of science. 

  • Mere; that and that only. 

  • Without harmonics or overtones; not harsh or discordant. 

  • A lot of. 

verb
  • to hit (the ball) completely cleanly and accurately 

noun
  • One who, or that which, is pure. 

adv
  • to a great extent or degree; extremely; exceedingly. 

rarefied

adj
  • Elevated in style or nature, sublime; of high intellectual or moral value. 

  • Distant from the lives and everyday concerns of ordinary people; esoteric, exclusive, select. 

  • Less dense than usual; thin. 

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