solicitude vs vigilance

solicitude

noun
  • Special or pronounced concern or attention. 

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

  • A cause of anxiety or concern. 

vigilance

noun
  • Close and continuous attention. 

  • Alert watchfulness. 

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