without notice; without permission; without leave
Used when someone does something, especially is absent or fails to follow a rule, without giving the required notice or obtaining leave. Common in compounds and phrases such as 無届け欠勤 and 無届けで.
If you are absent without notice, you may be subject to disciplinary action.
He repeatedly took unauthorized absences.
unregistered; unreported; not filed
Used for a status such as a marriage, business, or procedure not having been reported or registered. This sense as a confusion with 未届け; in careful writing, 未届け is often the more precise form for 'not yet reported/filed,' while 無届け emphasizes doing something without the required notification.
The unreported business operation became a problem.
The document explained that the marriage remained unreported.
He was fired after repeatedly being absent from work without notice.
It turned out the shop had been operating without proper registration.
The group held a demonstration without notifying the authorities.
Some couples remain married without ever registering it officially.