an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
any very difficult problem; insoluble in its own terms
lacking in insight or discernment; "too obtuse to grasp the implications of his behavior"; "a purblind oligarchy that flatly refused to see that history was condemning it to the dustbin"- Jasper Griffin