The antonyms for the phrase "took a nap" include actions that are the opposite of resting or sleeping. Some of these include engaging in physical activity such as exercising, working, or running errands. Another antonym could be focusing intensely on a task or project such as studying or completing work. Instead of napping, some people prefer to engage in stimulating mental activities like reading, writing or solving puzzles. Socializing or spending time with friends and family can also serve as an antonym to taking a nap. Overall, the opposite of taking a nap involves being active, productive, engaged, and alert.