impromptu

• The effort apparently was impromptu, and that added to its effect upon his auditors. —  My Memories of Eighty Years
• There was a bit of an impromptu (actually, "impromptu" is a bad term - a lot of people put in a lot of work to make it go off) show in Stanley Park last night. —  From Blown Speakers
• To honor that achievement, the coalition of Sunnis, Druze, Christians, and liberal Shi'a who had taken to the streets named their impromptu political alliance after this momentous date. —  City Journal
• But they are hardly impromptu, and they usually involve me carving on some sort of well-roasted carcas. —  The Food Whore
• The word impromptu is sufficiently self-explanatory, but it needs to be pointed out that this work of Schubert's differs from the usual impromptu in being an air with variations, the variations, however, giving the impression of free fantasies or improvisations on the original air. —  The Pianolist A Guide for Pianola Players

Roget's II: The New Thesaurus

Used in the Same Context