unprecedented

adj. /ʌnˈpresɪdentɪd/ C1

史无前例的；空前的

Never having happened or existed in the past.

仙境例句

A girl more than a mile high in court was unprecedented, so the King made a new rule.

法庭上出现一个一英里多高的女孩，这可是前所未有的，于是国王定了一条新规矩。