happening without anyone being told or warned in advance 未通知的;未预告的;未打招呼的 She just turned up unannounced on my doorstep. 她未打招呼就来到我家门口了。 an unannounced increase in bus fares 公共汽车票价未经公告的上涨
Oxford Collocations DictionaryUnannounced is used with these nouns:- visit
- arrive