Unattended means left with nobody looking after it. An unattended bag, do not leave unattended, unattended children.
It is a word of signs and announcements, and unattended baggage is the phrase every traveller has heard. On appliances it is a safety instruction: never leave a hob or a candle unattended.
1adjectiveunattendedLeft with nobody looking after it.
“Please do not leave your children unattended in the swimming pool.”
unattended is a state.
From un- + attended.
Etymology from Wiktionary, CC BY-SA