impromptu.

1. Made or done without advance preparation, often in response to the moment.

2. A musical piece with the character of an improvisation.

Use it for

Words that belong together

• impromptu meeting
• impromptu performance

On the page

An impromptu meeting formed around the recovered letter.

She gave an impromptu performance after the speaker withdrew.

Usage notes

Primary category: literary. Forms: Comparative more impromptu; superlative most impromptu where gradation is meaningful. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings.