unbeaufsichtigt
unsupervised
Without supervision or control by a responsible person; left alone.
Lassen Sie Ihr Gepäck am Flughafen niemals unbeaufsichtigt.
Never leave your luggage unattended at the airport.

unsupervised
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unsupervised
Without supervision or control by a responsible person; left alone.
Lassen Sie Ihr Gepäck am Flughafen niemals unbeaufsichtigt.
Never leave your luggage unattended at the airport.

The word is made up of the prefix 'un-' and 'beaufsichtigt' (supervised). 'Beaufsichtigt' is the past participle of the verb 'beaufsichtigen' (to supervise). So 'unbeaufsichtigt' literally means 'not supervised.'
Die spielenden Kinder waren für einen Moment unbeaufsichtigt.
The children playing were unsupervised for a moment.
The most common and important construction with this word is 'jemanden/etwas unbeaufsichtigt lassen' (to leave someone/something unattended). This pattern is often used in warnings or safety notices.
Man sollte kleine Kinder niemals unbeaufsichtigt in der Nähe von Wasser lassen.
You should never leave small children unattended near water.
Common nouns that occur in connection with 'unbeaufsichtigt' (unsupervised/unattended) are things that need protection or control. These include 'Kinder' (children), 'Gepäck' (luggage), 'Haustiere' (pets), or also 'ein offenes Feuer' (an open fire).
Lassen Sie Ihr Haustier an heißen Tagen nicht unbeaufsichtigt im Auto.
Do not leave your pet unattended in the car on hot days.
controlled
'kontrolliert' and 'unbeaufsichtigt' can be opposites when it comes to supervision and control. Here, 'kontrolliert' means that something is checked, monitored, or managed according to rules. 'Unbeaufsichtigt' means that no responsible person is watching over it. The words can be confusing because 'kontrolliert' can also mean self-controlled. In this pair, however, it is about external control. Remember: a controlled area is monitored; an 'unbeaufsichtigtes Kind' (unsupervised child) or 'unbeaufsichtigtes Gepäck' (unattended luggage) is left without supervision.

Im Schwimmbad dürfen kleine Kinder nicht unbeaufsichtigt bleiben.
At the swimming pool, small children must not be left unsupervised.
Der Zugang zum Labor ist kontrolliert, deshalb braucht jeder einen Ausweis.
Access to the laboratory is controlled, so everyone needs an ID.