Isaiah 9:18 (b) This represents the people of Israel in their character before GOD. They were useless, harmful and injurious, instead of being profitable and attractive.
Jeremiah 4:7 (b) The word is used to illustrate the evil surroundings and the wicked society of the countries of Assyria, Babylonia and other foreign nations which were to invade Israel and lay it waste. A thicket has no value to a farmer, but is to be destroyed. So these enemies were eventually to be destroyed by the Lord.