I. im-ˈpräm(p)-(ˌ)tü, -(ˌ)tyü noun
Etymology: French, from impromptu extemporaneously, from Latin in promptu in readiness
Date: 1683
1. : something that is impromptu
2. : a musical composition suggesting improvisation
II. adjective
Date: 1764
1. : made, done, or formed on or as if on the spur of the moment : improvised
2. : composed or uttered without previous preparation : extemporaneous
• impromptu adverb