字義:
Done without preparation or planning.
即席的；即興的；無準備的
Though delegates prepare hard before a MUN conference, you never know what is about to happen. You might have a good guess of what others have in mind on the issue, still the flow of discussion steers away easily to an unforeseen zone. Facing unexpected questions and situations, MUNers must react on the spot. Impromptu speech takes place most of the time and is a challenging yet rewarding skill. Distinguished delegates are often those apt in giving impromptu responses.
會議前模聯人總是奮力的備齊各種資料，但會議現場是很難捉摸的。即使你能夠大略揣測各國的立場、對議題的敏態度，準備的資料派不上用場、需要的資訊手無寸鐵是常有的事情。面臨始料未及的問題及會意走向，模聯人必須當機立斷，即刻反應。擅於即席的演說是模聯會議很重要的一環，是一項相得值得投資學習的挑戰。傑出的模聯代表往往是臨場反應快又精準的人。
例句:
He is a master at the craft of impromptu speeches.
他是即席演講達人。
Obama gave an impromptu press conference.
歐巴馬臨時舉行記者招待會。
