na-adjective
accidental; incidental; occasional; casual
Describes something that happens by chance, without planning or intention. Often used for events, encounters, or discoveries.
彼との再会はまったく偶発的だった。
My reunion with him was completely accidental.
An incidental problem occurred.
Compound of 偶発 (accidental occurrence) + 的 (-like, -ic). 偶発 is from 偶 (by chance) and 発 (occur).