Antonyms refer to words that have the opposite meanings of another word. For the phrase "takes effect," some possible antonyms include "fails to activate," "loses power," "has no impact," "becomes ineffective," or "ceases to work." These antonyms indicate a lack of impact or a reversal of the intended outcome, which stands in stark contrast to the original phrase's meaning. Identifying antonyms can be a valuable tool to expand one's vocabulary, contextual understanding, and cognitive flexibility, allowing for the clear expression of ideas and the ability to comprehend and interpret others' statements more accurately.