adjective / adverb / noun
impromptu
im-PRAHMP-too/ˌɪmprˈɑmptu/
Created on the occasion without prior preparation.
The adults interrupt meal preparation for an impromptu dance in the kitchen.

Etymology
Something “brought out” is ready at hand: the Latin expression meant “in readiness.” The English adjective shifts the emphasis to doing something on the spot, without advance planning.
In context
suggested another society for impromptu acting. Nothing is to be prepared beforehand.
More examples
- We hold an impromptu meeting in the hallway.
- Asked to say a few words, she speaks impromptu.
- The actors create a comic impromptu from the audience's suggestions.
Forms
impromptu · impromptus
Similar words
- spontaneous
- Stresses a natural impulse rather than lack of preparation.
- extemporaneous
- Usually describes speech or performance delivered without a script.
- improvised
- Emphasizes creating something as needed, often with limited resources.