Being master of something implies a sense of control, authority, and expertise. However, there are several antonyms that highlight the opposite meanings of this phrase. Firstly, one can be a novice or a beginner, lacking mastery and understanding. Secondly, being a follower or a subordinate would mean that one is not in a position of mastery, but instead, taking orders from another person. Thirdly, one can be struggling or grappling with something, indicating a lack of control or dominance. Fourthly, one can lose mastery over something, which means that they might have had the expertise once, but have now lost or forgotten it. Finally, being ignorant, apathetic, or disinterested in something shows a refusal to take control or master it.