contemplation vs thoughtlessness

contemplation

noun
  • The act of looking forward to a future event 

  • Holy meditation. 

  • The state of being considered or planned. 

  • The act of contemplating; musing; being highly concentrated in thought 

thoughtlessness

noun
  • heedless disregard for the consequences of one's actions 

  • disregard for other's feelings 

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