perplexity vs thoughtlessness

perplexity

noun
  • The state or quality of being perplexed; puzzled or confused. 

  • Something that perplexes. 

  • In information theory, a measurement of how well a probability distribution or model predicts a sample. 

thoughtlessness

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

  • disregard for other's feelings 

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