Something opposite or contrary to something else.
An opponent.
An antonym.
An additive inverse.
Located directly across from something else, or from each other.
Of leaves and flowers, positioned directly across from each other on a stem.
Facing in the other direction.
Of either of two complementary or mutually exclusive things.
Extremely different; inconsistent; contrary; repugnant; antagonistic.
In an opposite position.
Facing, or across from.
In a complementary role to.
On another channel at the same time.