'Unclean' in the Bible

Now in the synagogue there was a man who had the spirit of an unclean demon, and he cried out with a loud voice,

They were all amazed and began to say to one another, "What's happening here? For with authority and power he commands the unclean spirits, and they come out!"

and those who suffered from unclean spirits were cured.

As the boy was approaching, the demon threw him to the ground and shook him with convulsions. But Jesus rebuked the unclean spirit, healed the boy, and gave him back to his father.

"When an unclean spirit goes out of a person, it passes through waterless places looking for rest but not finding any. Then it says, 'I will return to the home I left.'