Answer:
understatement
Step-by-step explanation:
This is an understatement because Denise, according to the description, looks and feels really sick. On top of that, she looks as if she is about to get frostbite. She is no doubt going to have to skip a swim in the lake today, as well as other precautions for when people are sick, such as take medicine or stay in bed all day, which makes her saying an understatement.