アドリブ

あどりぶ
noun, na-adjective
ad-lib; improvisation
1. ad-lib; improvisation
Speaking or performing spontaneously without preparation or a script. Common in music, comedy, and acting.
This scene was performed ad-lib.
Improvisation is important in jazz.
He's good at improvising.

アドリブ refers to spontaneous, unscripted performance or speech. Borrowed from Latin "ad libitum" (at pleasure), via English.

COMMON PATTERNS:

USAGE:
Most commonly heard in entertainment contexts: ジャズ improvisation, comedy (漫才(まんざい), variety shows), theater, and film. Also used more broadly for any unscripted speaking, such as presentations or interviews. As a な-adjective: アドリブな対応(たいおう) (an improvised response).

CONTRAST: