There are several antonyms for the word "gat bottom," which refers to a baggy or saggy butt. One antonym is "toned" or "firm," indicating a well-shaped and muscular posterior. Another antonym could be "perky," suggesting a buttock that is lifted and youthful. Yet another antonym for "gat bottom" could be "svelte," denoting a slim and shapely backside. In any case, these antonyms emphasize the importance of regular exercise, a healthy diet, and maintaining a positive body image. It's essential to focus on improving overall health and fitness rather than obsessing over superficial physical attributes.