Didst, the archaic form of "did" that was used in Old English, is a word that has many antonyms. Some of the antonyms for didst include "didn't," "refused to," "abstained from," "neglected," "failed to," and "avoided." These antonyms are all related to the idea of not doing something that was expected or required. For example, if someone did not do something, they can be said to have "didn't" or "neglected" to do it. Similarly, if someone actively avoided doing something, they can be said to have "refused to" do it or "abstained from" doing it.