“idols.” The Hebrew text has the word 'eliyl (#0457 אֱלִיל), more literally “worthless ones,” a sarcastic name for “idols” (see commentary on Habakkuk 2:18, “worthless things”).
“a standing stone.” Although some standing-stones were set up as memorials, most standing-stones were set up as part of the worship of pagan gods, and that is the context here. God has no tolerance for idols. They are harmful in many different ways. They are to be destroyed. [For more on standing-stones, see commentary on Gen. 28:18. For more on idols being harmful, see commentary on Deuteronomy 7:5].