Definition of "impromptu" []

• Prompted by the occasion rather than being planned in advance: an impromptu party. (adjective)
• Spoken, performed, done, or composed with little or no preparation; extemporaneous: a few impromptu remarks. See Synonyms at extemporaneous. (adjective)
• With little or no preparation; extemporaneously. (adverb)
• Something, such as a speech, that is made or done extemporaneously. (noun)
• Music A short composition, especially for the piano, performed in an offhand or extemporized style. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "They are resourceful people and impromptu is the mode of operation they most relish."
• "Further away from the volcano, fears were rising that diseases could appear in impromptu refugee camps where scores of evacuees are now taking temporary shelter, unsure of when they might be able to return."
• ""What I find most disturbing about these stories is the fact that some of the news media take it upon themselves to disclose vital national security programs, thereby making it more difficult for us to prevent future attacks against the American people," Mr. Cheney said, in impromptu remarks at a fund-raising luncheon for a Republican Congressional candidate in Chicago."