'Unclean' in the Bible

I saw coming out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet, three unclean spirits, something like frogs;

He cried with a mighty voice, saying, "Fallen, fallen is Babylon the great, and she has become a habitation of demons, a prison of every unclean spirit, and a prison of every unclean and hateful bird!