accidentally vs fortuitously

accidentally

adv
  • In an accidental manner; by chance, unexpectedly. 

  • Unintentionally. 

fortuitously

adv
  • In a fortuitous manner; in a manner of happening by chance; coincidentally; accidentally. 

  • In a fortuitous manner; in a manner of happening by a lucky chance; luckily; fortunately. 

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