impromptu

Definitions

Done without being planned, organized, or rehearsed.

An unrehearsed or spontaneous performance or speech.

Examples

The team held an impromptu meeting to discuss the sudden changes in the project schedule.

She gave an impressive impromptu speech after being asked to step in at the last minute.

Synonyms

extemporaneous unrehearsed spontaneous improvised offhand unplanned ad-lib

Antonyms

planned rehearsed prepared scripted deliberate premeditated studied