n.

1. a word that expresses a meaning opposed to the meaning of another word, in which case the two words are antonyms of each other;
   antonym, opposite word
   
   • to him the antonym of `gay' was `depressed'
2. a relation of direct opposition;
   reverse, contrary
   
   • we thought Sue was older than Bill but just the reverse was true
3. a contestant that you are matched against;
   opposition, opponent
4. something inverted in sequence or character or effect;
   inverse
   
   • when the direct approach failed he tried the inverse

adj.

1. being 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
2. of leaves etc; growing in pairs on either side of a stem;
   paired
   
   • opposite leaves
3. moving or facing away from each other
   
   • looking in opposite directions
   • they went in opposite directions
4. the other one of a complementary pair
   
   • the opposite sex
   • the two chess kings are set up on squares of opposite colors
5. altogether 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
6. characterized by opposite extremes; completely opposed;
   diametric, diametrical, polar
   
   • in diametric contradiction to his claims
   • diametrical (or opposite) points of view
   • opposite meanings
   • extreme and indefensible polar positions

adv.

1. directly facing each other;
   face-to-face
   
   • 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