Sober-minded refers to a person who is serious, clear-headed, and focused. Some antonyms of sober-minded are carefree, reckless, and impulsive. A carefree person may not take things seriously and live in the moment without considering the consequences of their actions. Similarly, a reckless person may act without thinking and take unnecessary risks. An impulsive person may act on their emotions without considering the impact of their actions. Other antonyms of sober-minded include wild, uncontrolled, and thoughtless. These words highlight the opposite of being level-headed and rational, and instead, focus on being chaotic and irrational.