noun
Literary or formal noun meaning something unforeseen or happening by chance. Often used in set phrases like 不期の出来事 (unexpected event) or 不期の邂逅 (chance encounter). In everyday speech, 予期せぬ or 偶然 are more common.
不期の事故で計画が狂った。
The plan was disrupted by an unexpected accident.
旅先で不期の旧友に会った。
I met an old friend by chance on my trip.