An antonym is a word that means the opposite of another word. For example, "hot" and "cold" are antonyms, as are "good" and "bad". Antonyms can be all types of words: verbs, nouns, adjectives, adverbs, and more. The term "antonym" comes from "antonymy," which is the technical grammar term for words that have contradictory meanings.

Antonyms are closely related to synonyms, which are words that have identical meanings. While antonyms have opposite meanings, synonyms have the same meaning. There are different types of antonyms, including:

• Complementary antonyms: Also known as binary antonyms or contradictory antonyms, complementary antonyms are word pairs where the positive use of one means the negative use of the other. In other words, they have an either-or relationship: Something can be either one or the other but never both at the same time. Examples of complementary antonyms include "on" and "off" or "up" and "down".

• Gradable antonyms: These are antonyms that represent opposite ends of a spectrum. For example, "hot" and "cold" are gradable antonyms because there are varying degrees of temperature between them.

Antonyms can be helpful when reading, speaking, listening, or writing because they can help to clarify meaning and add nuance to language.