While the term "under thumb" implies control or dominance, antonyms for this phrase could include "independent," "self-sufficient," or "autonomous." These words convey a sense of freedom and self-reliance. Other antonyms to consider might be "empowered," "assertive," or "liberated." These words emphasize the idea of taking charge or being in control of one's own life. Additionally, antonyms could include "equal," "colleague," or "partner," highlighting the importance of mutual respect and reciprocity in relationships. Overall, adopting a vocabulary of antonyms for "under thumb" can help to promote individual agency, equality, and healthy interpersonal dynamics.