noun which may take the genitive case particle 'no', noun
not yet arrived; unarrived
Used attributively (with の) to describe something that has not yet arrived, such as mail, goods, or a person. Often seen in formal or logistical contexts.
未着の荷物がまだ届いていません。
The unarrived package has not been delivered yet.
未着のメールを確認してください。
Please check the emails that have not yet arrived.
Compound of 未 (み, 'not yet') and 着 (ちゃく, 'arrive'). The reading is the standard on'yomi for both characters.