accidently vs circumstantially

accidently

adv
  • Accidentally; by chance, unintentionally. 

circumstantially

adv
  • In respect to circumstances; not essentially; accidentally. 

  • in a circumstantial manner 

  • In every circumstance or particular; minutely. 

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