Antonyms are words that have opposite meanings to a particular word. In the case of the phrase "watched step," some antonyms could be reckless stride, carefree walk, or heedless stroll. These words suggest a lack of mindfulness, caution, and attention to one's surroundings, which is what the "watched step" phrase implies. By using antonyms, we can observe the different connotations and associations that words take on, which can aid in expressing ideas clearly and effectively. Therefore, being aware of antonyms helps us communicate ideas accurately and gain a better understanding of the nuances involved in language use.