Antonyms for the phrase "makes up one's mind" include words like indecisive, hesitant, vacillating, uncertain, and doubtful. These words denote a state of ambiguity, confusion, and lack of clarity. Being indecisive means being unable to make a decision, while being hesitant means being uncertain and slow to act. Vacillating shows a person who keeps changing their mind from one option to another, while being doubtful means having skepticism and mistrust. In contrast, making up one's mind denotes a state of certainty, resolution, and commitment. It is typically used to describe a person who has reached a decision after careful consideration and analysis.