coldness vs lethargy

coldness

noun
  • Limited enthusiasm or affection; coolness. 

  • The sensation resulting from exposure to low temperatures. 

  • The relative lack of heat. 

  • The reciprocal of absolute temperature. 

lethargy

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

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

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