Antonyms for the phrase "do duty as" can be found in words that convey a sense of inadequacy, disuse or refusal. Some of the commonly used antonyms for "do duty as" include "fail," "neglect," "depart," "unfit," "disuse," "abstain," "reject," and "slight." These antonyms are crucial in highlighting the negative aspects of avoiding one's responsibilities or not fulfilling one's obligations. Such acts may lead to negative consequences like missed opportunities, broken relationships, or even legal trouble in some cases. However, it's essential to note that the antonyms for "do duty as" may vary depending on the context, and it's important to choose the right word that accurately reflects the intended meaning.