a word that expresses a meaning opposed to the meaning of another word, in which case the two words are antonyms of each other
"to him the antonym of `gay' was `depressed'"
A word which has the opposite meaning of another word.
The word entered English in the mid-19th century from French antonyme, a term modeled on synonyme but originally influenced by the Ancient Greek word for "pronoun." It was popularized into common usage by Charles John Smith's 1867 book, which contrasted kindred words with their opposites.