ungebremst
unbraked
Without braking; at full speed and without reducing speed.
Das Auto fuhr ungebremst in die Mauer.
The car drove into the wall without braking.

unbraked / unchecked
Loading your saved state.
unbraked
Without braking; at full speed and without reducing speed.
Das Auto fuhr ungebremst in die Mauer.
The car drove into the wall without braking.

The word is the past participle of 'bremsen' (to brake) with the negative prefix 'un-'. So it literally means 'nicht gebremst' (not braked) and describes an action without a reduction in speed.
Der Radfahrer stürzte ungebremst vom Weg ab.
The cyclist went off the path without braking.
'Ungebremst' is very often used like an adverb to describe a verb of motion. In this case, it is not declined and usually appears at the end of the sentence or before a prepositional complement.
Der LKW raste ungebremst über die rote Ampel.
The truck raced through the red light without braking.
The literal meaning refers to vehicles and physical movement. You can recognize the figurative meaning from abstract nouns such as 'Wachstum' (growth), 'Konsum' (consumption), 'Fortschritt' (progress), or 'Ehrgeiz' (ambition).
Der ungebremste Konsum von Ressourcen schadet der Umwelt.
The unchecked consumption of resources harms the environment.
In the figurative meaning, 'ungebremst' (unchecked) is often combined with developments or processes. Common phrases are 'ungebremstes Wachstum' (unchecked growth), 'ungebremster Fortschritt' (unchecked progress), or 'ungebremste Kauflust' (unrestrained desire to shop).
Sein ungebremster Ehrgeiz machte ihn bei den Kollegen nicht beliebt.
His unchecked ambition made him unpopular with his colleagues.
controlled
'kontrolliert' and 'ungebremst' can form a clear contrast. 'kontrolliert' means that an action happens calmly, deliberately, and with self-control. In a figurative sense, 'ungebremst' means that something continues without restraint or control. This could be anger, enthusiasm, or growth, for example. 'kontrolliert' fits when someone or something remains limited and controlled. 'ungebremst' fits when something seems free, strong, and almost impossible to stop.

Die Kinder rennen ungebremst über den Schulhof.
The children run across the schoolyard without slowing down.
Nach der schlechten Nachricht spricht er kontrolliert weiter.
After the bad news, he continues speaking in a controlled way.