The antonyms for the phrase "acted the part of" include words like "ignored," "neglected," and "disregarded." These words reflect a lack of effort to play a role or perform a duty. Other antonyms for this phrase could be "abstained," "forsaken," or "abandoned." These words indicate intentionally avoiding the responsibility of acting a certain way or doing something. If one is not "acting the part," they may be "rebelling," "defying," or "resisting," indicating active opposition to the expected behavior. In general, words that describe a lack of conformity or disobedience can be considered antonyms for "acted the part of.