The phrase "keep eyes open" means to stay alert, watchful, and vigilant. Its antonyms are "ignore," "neglect," and "disregard." Ignoring is the act of paying no attention to something, while neglect is the failure to take care of something or someone. Disregard means to ignore or not take into consideration. If one is not keeping their eyes open, they are essentially neglecting or disregarding the situation around them. It's essential to keep one's eyes open in various circumstances, such as driving, walking on the street, or watching over a child, as it helps prevent accidents and keep oneself and others safe.