The antonyms for the term "filled one's position" can vary depending on the context. However, some possible antonyms might include "vacated one's position," "abandoned one's role," "left one's post," "shirked one's responsibility," or "resigned from one's position." These antonyms suggest a lack of commitment, responsibility, or dedication to a particular role or duty. In contrast, "filled one's position" implies a sense of duty, responsibility, and reliability. Therefore, using antonyms for this term can indicate the absence of these qualities or the failure to fulfill one's obligations in a particular role.