The word slim means slender or thin, The word “fat” means overweight or obese. Yet both “slim chance” and “fat chance” refer to something that is not likely to happen. For example, there is a slim chance of sunshine as it has been raining all day. Or, fat chance I will win a card game. I am not a good player. A video for people learning English from http://www.in30.tv Distributed by Tubemogul. Less