Bloodcurdling scream around castle when king’s assassinated (6)

I believe the answer is:

creepy

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Other definitions for creepy that I've seen before include "Disturbing and sinister" , "Eerie - chilling" , "Rather eerie" , "Eerie, uncanny" , "Causing a feeling of fear or unease" .)

I've seen this clue in The Hindu.

Want a hint initially instead of a full solution? Install my app