'Unclean Spirit' in the Bible

Then I saw three unclean spirits that looked like frogs coming out of the mouth of the dragon, out of the mouth of the beast, and out of the mouth of the false prophet.

He shouted with a powerful voice: "Fallen, fallen, is Babylon the great! She has become a lair for demons, a haunt for every unclean spirit, a haunt for every unclean bird, a haunt for every unclean and detested beast.