Unoccupied (adjective)

1. Not being used or lived in; vacant.
2. Not engaged in any activity or task; idle.

Origin:

Late middle english: from un- (expressing negation) + occupied.

Examples:

1. The house was unoccupied for several months.
2. The room was unoccupied.
3. The factory is currently unoccupied.
4. The building was unoccupied when the fire broke out.
5. The seat next to him was unoccupied.