The term that refers to a word that has the opposite meaning of another word is "antonym." For instance, in the English language, "hot" and "cold" are antonyms, as are "big" and "small." Antonyms play a significant role in language, enabling more precise and varied communication. They help define and clarify ideas by contrasting them with opposing concepts. Understanding antonyms enhances vocabulary and can improve both writing and speaking skills. In literature and everyday conversation, using antonyms effectively can contribute to richer, more engaging discourse.