serendipitously
Definitions
In a manner that occurs by chance in a happy or beneficial way.
Happening by fortunate accident or pleasant surprise.
Examples
I serendipitously found my lost keys while I was cleaning out the garage.
The two old friends serendipitously bumped into each other at a crowded airport in a foreign country.
Synonyms
by chance accidentally fortuitously coincidentally by happy accident flukily
Antonyms
deliberately intentionally by design purposely planned methodically