'Foul' in the Bible

But in the synagogue there was a man possessed by the spirit of a foul demon. In a loud voice he cried out,

All were astonished and awe-struck; and they asked one another, "What sort of language is this? For with authority and real power He gives orders to the foul 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;"