fortuitous

fortuitous is an   Adverb

Definition:

[1] Happening by chance; coming or occuring unexpectedly, or without any known cause; chance; as, the fortuitous concourse of atoms. It was from causes seemingly fortuitous . . . that all the mighty effects of the Reformation flowed. Robertson. So as to throw a glancing and fortuitous light upon the whole. Hazlitt.

[2] Happening independently of human will or means of foresight; resulting from unavoidable physical causes. Abbott.

Synonyms: