exertion vs idleness

exertion

noun
  • An expenditure of physical or mental effort. 

idleness

noun
  • Groundlessness; worthlessness; triviality; vanity; frivolity. 

  • The state of being idle; inactivity. 

  • The state of being indolent; indolence. 

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