Definitions of opposite:

• noun:   something inverted in sequence or character or effect
• noun:   two words that express opposing concepts

  Example: "To him the opposite of gay was depressed"

• noun:   a contestant that you are matched against
• noun:   a relation of direct opposition
• adjective:   of leaves etc; growing in pairs on either side of a stem

  Example: "Opposite leaves"

• adjective:   altogether different in nature or quality or significance

  Example: "The medicine's effect was opposite to that intended"

• adjective:   the other one of a complementary pair

  Example: "The opposite sex"

• adjective:   being directly across from each other; facing

  Example: "And I on the opposite shore will be, ready to ride and spread the alarm- Longfellow"

• adjective:   moving or facing away from each other

  Example: "Looking in opposite directions"

• adjective:   characterized by opposite extremes; completely opposed

  Example: "Diametrical (or opposite) points of view"

• adverb:   directly facing each other

  Example: "They sat opposite at the table"