The phrase "last duty" generally refers to the final responsibility or obligation one has before completing a task or leaving a position. Some common synonyms for this phrase include final task, last obligation, ultimate responsibility, end duty, concluding duty, final responsibility, ultimate obligation, closing task, and ultimate task. These synonyms all convey a sense of finality and completion, emphasizing the importance of finishing strong and fulfilling one's duties to the best of their ability. Whether in the workplace, at home, or in any other area of life, completing one's last duty is a crucial step in achieving success and moving forward to new opportunities.