The phrase "didst u-turn" is quite specific and may not have many close synonyms. However, some words and phrases that could be used instead include "made a turnaround," "reversed course," "changed direction abruptly," or simply "u-turned." These words can be used in various contexts when describing a sudden change in plans or decisions. It is important to select the right word or phrase depending on the specific situation being described. Using synonyms effectively can help create more variety in language and convey a message with precision and accuracy.