'Foul' in the Bible

There was a man in the synagogue who was possessed by the spirit of an unclean demon; and he cried out with a loud and terrible voice,

They were all astonished and in awe, and began saying to one another, “What is this message? For with authority and power He commands the unclean spirits and they come out!”

and those who were tormented by foul spirits were cured.

For already He had been commanding the foul spirit to come out of the man. For many a time it had seized and held him, and they had repeatedly put him in chains and fetters and kept guard over him, but he used to break the chains to pieces, and, impelled by the demon, to escape into the Desert.

Now while the youth was coming, the spirit dashed him to the ground and cruelly convulsed him. But Jesus rebuked the foul spirit, and cured the youth and gave him back to his father.

"When a foul spirit has left a man, it roams about in the Desert, seeking a resting-place; but, unable to find any, it says, 'I will return to the house I have left;"