noun, noun which may take the genitive case particle 'no'
ad lib; improvisation
Used for spontaneous performance, speech, or action without preparation. Common in music, theater, and everyday conversation.
from Latin
彼のスピーチは完全にアドリブだった。
His speech was completely ad-libbed.
アドリブでギターを弾いてみて。
Try playing the guitar off the cuff.