adventitious
Definitions
Happening or carried on according to chance rather than design or inherent nature.
Coming from outside; not native or innate.
In biology, occurring in an unusual or abnormal place, such as a root growing from a stem.
Examples
The plant developed adventitious roots from its stem, allowing it to propagate in the damp soil.
His success was largely adventitious, resulting from a series of fortunate events rather than careful planning.
Synonyms
accidental fortuitous incidental extraneous unplanned chance