Keep under thumb typically means to exercise control or dominance over someone. Its antonyms would mean the opposite - to let someone be free and in control of their own choices and decisions. Some suitable antonyms for this phrase might include "release," "unleash," "liberate," "set free," "give autonomy," and "empower." When we choose to trust and respect others, we can honor their autonomy, individuality, and freedom - rather than keeping them under our thumb. It's important to recognize the value and worth of other people, allowing them to live their lives and make their decisions in a way that aligns with their own values and beliefs.