The phrase "did thing" is not a specific word, but rather a colloquialism that describes a specific action or deed that someone has done. Some antonyms for the phrase might include "didn't do anything," "ignored," or "failed to act." These words imply a sense of apathy or negligence, indicating that the person in question did not take any proactive steps to achieve a particular goal or to address a problem. Other potential antonyms might include words like "undo," "reverse," or "unmake," which suggest the opposite of doing something - namely, undoing or undoing a previous action.