Add to word list done or said without earlier planning or preparation: an impromptu speech (Definition of impromptu from the Cambridge Academic Content Dictionary © Cambridge University Press) impromptu meaning , definition, what is impromptu : done or said without any preparation or ...: Learn more. Impromptu definition: made or done without previous preparation .. See examples of IMPROMPTU used in a sentence. An impromptu action is one that you do without planning or organizing it in advance . This afternoon the Palestinians held an impromptu press conference. The children put on an impromptu concert for the visitors.
