From King Dictionary of Contemporary Englishimpromptuim‧promp‧tu /ɪmˈprɒmptjuː $ ɪmˈprɑːmptuː/ adjective PLANdone or said without any preparation or planningimpromptu speech/party/meeting etc The band gave an impromptu concert.impromptu adverb
Examples from the Corpus
impromptuThe remarks of both Clintons were, at least in part, impromptu.The drunken revel of the Roman leaders has the right air of impromptu festivity.We finished the day with an impromptu game of football in a nearby field.I could then have pretended to notice him for the first time and have engaged him in conversation in an impromptu impromptu performanceSchwarm disputed the witness' story last week in an impromptu press conference outside court.But in the final hour he did deliver the goods, taking impromptu questions from the audience.He had failed because of a lack of talent for impromptu speaking, considered essential for the task he was contemplating.Jem's impromptu speech met with thunderous applause.But if friends descended, would you be ready to rustle up an impromptu supper?From that point, the forum became an impromptu tribute to Jim Maier.impromptu speech/party/meeting etcThen an impromptu meeting, on the model of what had happened in Dungannon, was held.
Origin impromptu (1600-1700) French Latin in promptu in readiness