What does it mean by off-the-cuff line?
Native speaker’s answer
Rebecca
The phrase "off the cuff" is used to say that someone speaks without pre-planning or rehearsal. It is an idiom that is most commonly used in daily speech as it would not be considered very formal. "Line" here simply means sentence or phrase. So the President is thanking him for that joke which he thinks came without planning. Ex: I didn't prepare a speech, so I will just say a few words off the cuff. Ex: Jon has a habit of making off-the-cuff remarks that he later regrets.