The phrase not even wrong describes any argument that purports to be scientific but fails at some fundamental level. The phrase is often used to describe pseudoscience or bad science, and is considered derogatory.
The phrase is generally attributed to theoretical physicist Wolfgang Pauli, who was known for his colorful objections to incorrect or sloppy thinking.
The origin story is supposed to be that a friend showed Pauli the paper of a young physicist which he suspected was not of great value but on which he wanted Pauli's views. Pauli remarked sadly, "It is not even wrong."
A variation is "It is not only not right, it is not even wrong."