The term "rattled cage" typically refers to a situation where someone feels uncomfortable, frustrated, or irritated. It can also be associated with a feeling of being trapped or confined. When looking at antonyms for this phrase, some words that come to mind include peaceful, calm, relaxed, comfortable, content, secure, and free. These words suggest a sense of tranquility and ease, where there is no tension, agitation or unrest. Instead, there is a feeling of safety, stability, and a lack of disturbance. These words act as a contrast to the idea of a rattled cage, creating a sense of balance and harmony.