ADJ [usu ADJ after v, ADJ n, oft v-link ADJ]未事先通知的;未提前说明的;未打招呼的 If someone arrives or does something unannounced, they do it unexpectedly and without anyone having being told about it beforehand. 未事先通知的;未提前说明的;未打招呼的
He had just arrived unannounced from South America.
他刚刚从南美来到这里,事先没有打招呼。
My first night in Saigon I paid an unannounced visit to my father's cousins.