noun which may take the genitive case particle 'no'
untitled; without a title; no subject (email)
Describes a work, message, or item that has no title. Common in art, music, and email contexts.
This piece was released untitled.
無題のメールは迷惑メールと間違えられやすい。
Emails with no subject are easily mistaken for spam.
Compound of 無 (mu, 'without') and 題 (dai, 'title'). The reading is on'yomi.