Jeremiah 51:17 Every man is brutish by his knowledge; Every founder is confounded by the graven image: For his molten image is falsehood, and there is no breath in them. 18 They are vanity, the work of errors: In the time of their visitation they shall perish.
The word is strong. It means stupid, brute. They make images thinking that the handmade images can do something. There is no life in what they make. They are empty, worthless. They will not stand up when trouble comes.
They might make a pretty decoration but they will not accomplish anything because they are just things made with hands.
How often do we build up our own gods? We make our own way and expect it to work. We need to know that God is real. He made us. He is all powerful. He is to be obeyed, honored, respected, and feared.
Do not turn to your own way but to His! Only someone with brute intelligence would think that he could make a god that could do something for him!