impromptus

adjective

1. made or done without previous preparation: an impromptu address to the unexpected crowds.
2. suddenly or hastily prepared, made, etc.: an impromptu dinner.
3. improvised; having the character of an improvisation.

adverb

4. without preparation: verses written impromptu.

noun

5. something impromptu; an impromptu speech, musical composition, performance, etc.
6. a character piece for piano common in the 19th century and having, despite its title, a clear-cut form.

adjective

1. unrehearsed; spontaneous; extempore
2. produced or done without care or planning; improvised

adverb

3. in a spontaneous or improvised wayhe spoke impromptu

noun

4. something that is impromptu
5. a short piece of instrumental music, sometimes improvisatory in character

1660s (adv.), 1764 (adj.), from French impromptu (1650s), from Latin in promptu “in readiness,” from assimilated form of in- “into, in, on, upon” (see in- (2)) + promptu, ablative of promptus “readiness,” from past participle of promere “to bring out,” from pro- “before, forward, for” + emere “to obtain” (see exempt).