off the cuff idiom
未经准备;未加思索;即兴地
If you speak off the cuff, you say something without having prepared or thought about your words first.
I hadn't prepared a speech so I just said a few words off the cuff. 我没准备发言，所以就随便说了几句。
[ before noun ] an off-the-cuff remark 即兴评论