The phrase "watches one's step" implies being careful and cautious in one's actions or decisions. Antonyms, or words with opposite meanings, include reckless, careless, inattentive, and thoughtless. Reckless actions involve little regard for consequences or potential danger, while careless actions are done without care or attention to detail. Someone who is inattentive may not be paying close attention to their surroundings or actions, while a thoughtless person may not consider the impact of their words or actions on others. Overall, the antonyms for "watches one's step" suggest a lack of mindfulness and a disregard for potential consequences.