forgetfulness vs reflection

forgetfulness

noun
  • Failure to bear in mind; careless omission; inattention. 

  • Loss of remembrance or recollection; a ceasing to remember; oblivion. 

  • The quality of being forgetful; proneness to let slip from the mind. 

reflection

noun
  • Careful thought or consideration. 

  • The act of reflecting or the state of being reflected. 

  • The process or mechanism of determining the capabilities of an object at run-time. 

  • The folding of a part; a fold. 

  • Something, such as an image, that is reflected. 

  • The property of a propagated wave being thrown back from a surface (such as a mirror). 

  • An implied criticism. 

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