sloth vs weariness

sloth

noun
  • Laziness; slowness in the mindset; disinclination to action or labour. 

  • A herbivorous, arboreal South American mammal of the families Megalonychidae and Bradypodidae, noted for its slowness and inactivity. 

  • A collective term for a group of bears. 

weariness

noun
  • Exhaustion, fatigue or tiredness. 

  • A lack of interest or excitement. 

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