名詞 impromptu:

1. an extemporaneous speech or remark
2. a short musical passage that seems to have been made spontaneously without advance preparation

形容詞 impromptu:

1. with little or no preparation or forethought
   同義詞：ad-lib, extemporaneous, extemporary, extempore, offhand, offhanded, off-the-cuff, unrehearsed

副詞 impromptu:

1. without advance preparation
   同義詞：ad lib, ad libitum, spontaneously

1. An impromptu visit broke up the long afternoon.
   突然的造訪打破了漫長的午后時光
2. It usually take me more than three weeks to prepare a good impromptu speech.
   為了準(zhǔn)備一則即席的好講辭，我通常要三個星期以上。

im.promp.tu

adj.（形容詞）
Prompted by the occasion rather than being planned in advance:
即興的：即興的而不是事先有準(zhǔn)備的：
例句：
an impromptu party.
即興的聚會

Spoken, performed, done, or composed with little or no preparation; extemporaneous:
即席的，無準(zhǔn)備的：毫無準(zhǔn)備地說、表演、做或作曲的；臨場的：
例句：
a few impromptu remarks.See Synonyms at extemporaneous
一些臨場的評論參見 extemporaneous

adv.（副詞）
With little or no preparation; extemporaneously.
沒有準(zhǔn)備地；臨場地
n.（名詞）
Something, such as a speech, that is made or done extemporaneously.
即興作的東西，如講演
Music A short lyrical composition especially for the piano.
【音樂】 即興曲：一則短的抒情曲子，特別是鋼琴曲

來源：
French
法語
from Latin in prômptô [at hand]
源自 拉丁語 in prômptô [手頭的]
in [in] * see in- 2
in [在…里面] *參見 in-2
prômptô [ablative of] prômptus [readiness] [from past participle of] prômere [to bring forth] * see prompt
prômptô [] prômptus的奪格 [機智] [] 源自prômere的過去分詞 [產(chǎn)生] *參見 prompt