ad-lib
verb [intransitive, transitive]to say something in a speech or a performance that you have not prepared or practised synonym improvise即席讲话;即兴表演 She abandoned her script and began ad-libbing. 她抛开脚本即兴表演起来。 - ad-lib something
I lost my notes and had to ad-lib the whole speech. 我把讲稿弄丢了,只好临时说了一通。 He ad-libbed his way through the meeting. 他在会议中即兴发挥。
Word Originearly 19th cent. (as an adverb): abbreviation of ad libitum.