out of bounds

Short definition from Wiktionary

Prepositional phrase

1. 1
   Where one is prohibited to enter.
2. 2
   Beyond the bounds of civility, morality, or normality.
3. 3
   Outside the area of play; beyond the sideline of a playing field or court.

Noun

1. 1
   A sideline marking the edge of a playing field or court.
2. 2
   An instance of a player or the ball going out of bounds.
3. 3
   Ground that one is not permitted to enter, or that is outside the permitted playing area.
4. 4
   Alternative form of out of bounds.