No doubt about it. This is a creepy word.
It’s interesting, because unquiet is not the opposite of the word quiet in its most usual meaning. It doesn’t mean noisy or loud. Unquiet relates to restlessness, turbulence and anxiety.
The word unquiet is most usually paired with is “spirits”.

Other words I found it paired with, doing a quick and dirty Google search, were: “dead”, “graves”, “ghost”, “dreams”, “past”, “mind” and “earth”. So it definitely has overtones of the spiritual, emotional and the macabre.
I like this word because the very fact of it being an un- word implies the most desirable state of whatever is being described is one of quiet. The fact that it has become unquiet is ominous, even unnatural.
Unquiet is a lovely word, just dripping with story.
I hope you had a great Halloween.