impromptu

1. ADJ An impromptu action is one that you do without planning or organizing it in advance. 無(wú)事先準(zhǔn)備的

This afternoon the Palestinians held an impromptu press conference. 今天下午巴勒斯坦人召開(kāi)了一場(chǎng)臨時(shí)記者招待會(huì)。