A “roast” is a form of humor in which a person or group of people are subjected to good-natured insults and jokes. “Roast lines” are the individual jokes or insults that are delivered during a roast.
Best roast lines are clever, funny, and often personal. They are designed to make the subject of the roast laugh, even if they are also a little bit embarrassed. Roasts can be a lot of fun, but it is important to remember that they are all in good fun. The best roasts are those that are delivered with respect and affection.