impromptu

/ɪmˈpɹɒmptju/noun

A piece of music, speech, or other creation produced on the spur of the moment, without any preparation.

Example sentence

“She sat down at the piano and played a short impromptu for the guests.”

Commonly an adjective: an impromptu speech, an impromptu party. From the Latin phrase 'in promptu', in readiness.

Related words

improviseTo create or perform something on the spot, relying on instinct and imagination instead of a prepared plan.impressiveCausing admiration; having a strong positive effect on people.impudentRude and disrespectful in a bold, shameless way.imposingTo use authority to make people accept a rule, charge, or burden.inadvertentDone by accident, without meaning to or noticing.imposeTo put a rule, tax, or duty in place using official power.