The phrase "is of mind" refers to one's state of consciousness or mental disposition. Antonyms for this phrase may include "out of mind," meaning insane or mentally unstable, and "unmindful," meaning lacking awareness or attention. Other antonyms could be "clear-headed," "sensible," or "lucid," implying a sense of mental clarity and rational thinking. Additionally, terms like "emotionless," "indifferent" and "detached" may also serve as antonyms for "is of mind," as they connote a lack of emotional involvement or investment in a situation. Ultimately, the antonyms for "is of mind" depend on the context and intended meaning of the phrase.