The phrase "out one's mind" represents a state of being irrational or insane. The antonyms for this phrase are words that signify mental stability, sanity, and rationale. These antonyms include "composed," "balanced," "sane," "together," "calm," and "collected." When someone exhibits these characteristics, it means that they have a grip on their emotions and actions, and they have an understanding of the impact of their decisions. Being level-headed and achieving a state of mental balance require consistent effort and self-reflection. It is crucial to recognize the importance of being composed, especially in situations that require logical thinking and decision-making.