'Impromptu' definitions:

Definition of 'impromptu'

(from WordNet)
adverb
Without advance preparation; "he spoke ad lib" [syn: ad lib, ad libitum, spontaneously, impromptu]
adjective
With little or no preparation or forethought; "his ad-lib comments showed poor judgment"; "an extemporaneous piano recital"; "an extemporary lecture"; "an extempore skit"; "an impromptu speech"; "offhand excuses"; "trying to sound offhanded and reassuring"; "an off-the-cuff toast"; "a few unrehearsed comments" [syn: ad-lib, extemporaneous, extemporary, extempore, impromptu, offhand, offhanded, off-the-cuff, unrehearsed]
noun
An extemporaneous speech or remark; "a witty impromptu must not sound premeditated"
noun
A short musical passage that seems to have been made spontaneously without advance preparation

Definition of 'Impromptu'

From: GCIDE
  • Impromptu \Im*promp"tu\, adv. or a. [F. impromptu, fr. L. 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. [1913 Webster]

Definition of 'Impromptu'

From: GCIDE
  • Impromptu \Im*promp"tu\, n.
  • 1. Something made or done offhand, at the moment, or without previous study; an extemporaneous composition, address, or remark. [1913 Webster]
  • 2. (Mus.) A piece composed or played at first thought; a composition in the style of an extempore piece. [1913 Webster]