The antonyms for the phrase "acquitting oneself" largely revolve around negative connotations such as being guilty or culpable. Some possible antonyms could include terms like "conviction," "implication," or "reproach." Other options might include phrases like "failing to be blameless," "being found guilty," or "falling short of expectations." Essentially any term that suggests a failure to live up to certain standards or expectations can be considered an antonym for the more positive phrase "acquitting oneself." Ultimately, the specific antonym chosen will depend on the context of the phrase and the overall tone of the surrounding text.