n. 反义词

[ noun ]
a word that expresses a meaning opposed to the meaning of another word, in which case the two words are antonyms of each other
<noun.communication>
to him the antonym of `gay' was `depressed'

Antonym \An"to*nym\, n. [Gr. ? a word used in substitution for
another; ? + ?, ?, a word.]
A word of opposite meaning; a counterterm; -- used as a
correlative of synonym. [R.] --C. J. Smith.