interest vs lethargy

interest

verb
  • To engage the attention of; to awaken interest in; to excite emotion or passion in, in behalf of a person or thing. 

noun
  • A great attention and concern from someone or something; intellectual curiosity. 

  • An involvement, claim, right, share, stake in or link with a financial, business, or other undertaking or endeavor. 

  • The price paid for obtaining, or price received for providing, money or goods in a credit transaction, calculated as a fraction of the amount or value of what was borrowed. 

  • Condition or quality of exciting concern or being of importance. 

  • Any excess over and above an exact equivalent 

  • The persons interested in any particular business or measure, taken collectively. 

  • Something or someone one is interested in. 

  • Attention that is given to or received from someone or something. 

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