The antonyms for "improve mind" would be words that describe the opposite of enhancing one's intellectual capacity. Some of these words include words such as "worsen", "stagnate", "decline", "deteriorate", "regress", "degenerate", "retrogress," and "debase." When our minds are not adequately stimulated, our cognitive abilities will deteriorate, causing a reduction in attention span, memory, and decision-making skills. By not working to enhance our mental faculties, we risk falling into a state of stagnancy or decline, leading to unproductive and unfulfilling lifestyles. Therefore, it is critical to engage in activities such as reading, challenging brain games, and learning new skills to ensure that we are continuously improving our minds.