waist trainer is a garment worn around the waist, usually made of a stretchy and compressive material like latex or spandex. The goal of a waist trainer is to create a slimmer and more defined waistline by compressing the midsection and redistributing fat. Waist trainers have become popular in recent years, particularly among women who want to achieve an hourglass figure. Some people also use waist trainers during workouts to enhance their sweat output and promote weight loss.