solicitude vs thoughtlessness

solicitude

noun
  • The state of being solicitous; uneasiness of mind occasioned by fear of evil or desire for good; anxiety. 

  • Special or pronounced concern or attention. 

  • A cause of anxiety or concern. 

thoughtlessness

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

  • disregard for other's feelings 

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