(n)antonym, opposite word, oppositea 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'”
(s)oppositebeing directly across from each other; facing“And I on the opposite shore will be, ready to ride and spread the alarm” (Longfellow), “we lived on opposite sides of the street”, “at opposite poles”
(s)oppositealtogether different in nature or quality or significance“the medicine's effect was opposite to that intended”, “it is said that opposite characters make a union happiest” (Charles Reade)
(r)face-to-face, face to face, oppositedirectly facing each other“the two photographs lay face-to-face on the table”, “lived all their lives in houses face-to-face across the street”, “they sat opposite at the table”