The phrase "of own accord" implies that someone is acting or behaving voluntarily without any external force or compulsion. Therefore, some possible antonyms for this phrase might include "under duress," "coerced," "compelled," "forced," or "obliged." These words suggest a sense of pressure, obligation, or even violence that is absent from the notion of acting "of own accord." Other antonyms that convey a sense of external influence might include "manipulated," "persuaded," "convinced," or "influenced." While the opposite of acting "of own accord" may depend on the specific context in which the phrase is used, these antonyms provide a range of possibilities for expressing the opposite meaning.