beängstigend
frightening
Causing fear or anxiety; seeming eerie or threatening.
Die Stille im alten Haus war beängstigend.
The silence in the old house was frightening.

frightening
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frightening
Causing fear or anxiety; seeming eerie or threatening.
Die Stille im alten Haus war beängstigend.
The silence in the old house was frightening.

'Beängstigend' (frightening) is the present participle of the verb 'beängstigen' (to frighten). This verb is derived from the noun 'die Angst' (fear). So the form describes something that actively creates or causes fear.
Er erzählte eine beängstigende Geschichte vom Krieg.
He told a frightening story about the war.
The ending '-end' (present participle) signals that something has a quality or performs an action. So 'beängstigend' (frightening) describes the thing that *causes* fear, not the person who *feels* fear.
Die Geschwindigkeit des Autos war beängstigend.
The speed of the car was frightening.
'Beängstigend' (frightening) can also be used as an adverb to intensify another adjective or adverb. In that case it means something like 'shockingly' or 'extremely'.
Das Wasser war beängstigend kalt.
The water was frighteningly cold.
creepy / very
'unheimlich' and 'beängstigend' both describe something that can cause fear or unease. 'unheimlich' often fits strange, mysterious, or creepy situations where you do not feel comfortable. 'beängstigend' is more direct and more strongly related to real fear or danger. A dark street can seem 'unheimlich' (creepy); a rapid deterioration in health can be 'beängstigend' (frightening). Learners may confuse the words because both have to do with fear. If it is more about creepiness or a strange feeling, 'unheimlich' is more natural. If something really causes fear or seems threatening, 'beängstigend' is more precise.

Bei schlechtem Wetter ist die Fahrt über die alte Brücke beängstigend.
In bad weather, the drive over the old bridge is frightening.
Vor dem Termin war es im leeren Wartezimmer unheimlich still.
Before the appointment, it was creepily quiet in the empty waiting room.