Impromptu
Impromptu , adv. o a.
[French impromptu, from Latin in promptu in readiness, at hand; in in + promptus visibility, readiness, from promptus visible, ready. See Prompt.]
Offhand; without previous study; extemporaneous; extempore; as, an impromptu verse.
Impromptu , noun
1.
Something made or done offhand, at the moment, or without previous study; an extemporaneous composition, address, or remark.
2.
(Music) A piece composed or played at first thought; a composition in the style of an extempore piece.