VERB
即兴演出，临时插入（脚本或讲稿中没有的台词）
If you ad-lib something in a play or a speech, you say something which has not been planned or written beforehand.
例句
He began comically ad-libbing a script...
他即兴调侃起了一段剧本。
He's good at ad-libbing his way out of trouble...
他善于为自己妙语解围。