The phrase "cross mind" typically refers to an idea or thought that briefly comes to mind before being dismissed or forgotten. Antonyms for this phrase might include terms like "persistent thought," "undivided focus," or "unwavering attention." These words convey the opposite of the fleeting and temporary nature of "cross mind," instead suggesting a deep concentration or ongoing contemplation of a particular topic. Other antonyms might include terms like "clarity of purpose," "single-mindedness," or "steadfast concentration," all of which imply a sense of determination, commitment, and unwavering focus. So, while "cross mind" suggests a fleeting thought, its antonyms suggest qualities associated with successful goal achievement.