emotion vs lethargy

emotion

noun
  • A person's internal state of being and involuntary physiological response to an object or a situation, based on or tied to physical state and sensory data. 

  • A reaction by a non-human organism with behavioral and physiological elements similar to a person's response. 

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 emotion and lethargy occurred in a corpus of books? (source: Google Ngram Viewer )