An unresolved issue; an outstanding problem; an unsettled matter or case.
那起陈年旧案至今仍是警方内部的一桩未了公案，许多谜团尚未解开。
That cold case remains an unresolved issue within the police department to this day, with many mysteries yet to be unraveled.
Next Idiom
An unresolved issue; an outstanding problem; an unsettled matter or case.