Unattended (adjective)

1. Not watched over or looked after; not having someone present.
2. Not given attention or consideration.

Origin:

From un- + attended, first recorded in the late 16th century.

Examples:

1. The store was left unattended while the owner was on vacation.
2. The child was unattended and got into trouble.
3. The fire was unattended and quickly spread.
4. The meeting was unattended and had to be rescheduled.
5. The wound was unattended and became infected.