appetite vs lethargy

appetite

noun
  • Desire to eat food or consume drink. 

  • The desire for some personal gratification, either of the body or of the mind. 

  • Any strong desire; an eagerness or longing. 

lethargy

noun
  • A condition characterized by extreme fatigue or drowsiness, deep unresponsiveness, or prolonged sleep patterns. 

  • A state of extreme torpor or apathy, especially with lack of emotion, energy or enthusiasm; (loosely) sluggishness, laziness. 

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