The antonyms for the phrase "crept up" are words that describe sudden, extreme or rapid movements, such as bolted, dashed, leapt or sprang. These words suggest quick and decisive action, in contrast to the slow, sneaky and stealthy movement implied by "crept up". Other antonyms might include retreat, or withdraw, which describe movements away from a location or object, rather than towards it. Overall, the antonyms for "crept up" evoke a sense of speed, power and energy, and imply active rather than passive engagement with the world.