'Unclean' in the Bible

And there was in the synagogue a man having a spirit of an unclean demon, and he cried with a loud voice,

And astonishment came upon all, and they spoke to one another, saying, What word is this? for with authority and power he commands the unclean spirits, and they come out.

and those that were beset by unclean spirits were healed.

For he had commanded the unclean spirit to go out from the man. For very often it had seized him; and he had been bound, kept with chains and fetters; and breaking the bonds he was driven by the demon into the deserts.

But as he was yet coming, the demon tore him and dragged him all together. And Jesus rebuked the unclean spirit, and healed the child and gave him back to his father.

When the unclean spirit has gone out of the man, he goes through dry places seeking rest; and not finding any he says, I will return to my house whence I came out.