The phrase "lift a voice" means to speak out or make a sound, usually in a loud and firm manner. The antonyms, or opposite words, for this phrase could include "stay silent," "remain quiet," or "keep quiet." Other antonyms could be "mumble," "whisper," or "speak softly." These words suggest a lack of confidence or assertiveness. Additionally, "shy away," "back down," or "concede" could be antonyms for "lift a voice" as they imply a reluctance to speak out or take a stand. Overall, the antonyms for "lift a voice" offer a range of options for those who prefer to express themselves in a more subdued or reserved manner.