General:
* Spacious
* Roomy
* Ample
* Expansive
* Open
* Airy
* Comfortable
Specific:
* Spacious: For a large area, like a room.
* Roomy: For a smaller area, like a car.
* Ample: For a sufficient amount of space.
* Expansive: For a wide and open area.
* Open: For a lack of barriers or restrictions.
* Airy: For a light and well-ventilated area.
* Comfortable: For a pleasant and relaxing space.
The best opposite will depend on the specific situation you are describing.