If something that has happened was ~, it was not expected to happen or known about beforehand.
Radiation may damage cells in a way that was previously ~...
Unfortunately, due to ~ circumstances, this year’s show has been cancelled...
ADJ
If something that has happened was ~, it was not expected to happen or known about beforehand.
Radiation may damage cells in a way that was previously ~...
Unfortunately, due to ~ circumstances, this year’s show has been cancelled...
ADJ
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012