unannounced
adjective, adverb uk/ˌʌn.əˈnaʊnst/ us/ˌʌn.əˈnaʊnst/
（某人的到来）未通知的（地），未打招呼的（地）;突然的（地）
If someone arrives unannounced, they arrive suddenly and unexpectedly.
She appeared unannounced and took control of the meeting. 她突然出现并控制了会议。
unannounced
adjective uk/ˌʌn.əˈnaʊnst/ us/ˌʌn.əˈnaʊnst/
未宣布的，未公布的
not made publicly known
The Texan singer will be supported by two other bands, as yet unannounced. 这位得克萨斯歌手将由另外两支乐队伴奏，但还没公布是哪两支乐队。