Accidentally
Part of speech: adverb
Definition: In an accidental manner; unexpectedly; by chance; casually; fortuitously. Unintentionally.
Example sentence: I accidentally met Don Callis in Japan. I was at New Japan and I was with mutual friends, and I met Don on accident and started telling him some of my ideas. We started talking and he basically at dinner was saying, 'Hey, we should give you a job.'
Unintentionally
Part of speech: adverb
Definition: In an unintentional manner; not intentionally.