From Longman Dictionary of Contemporary EnglishGordian knotGor‧di‧an knot /ˌɡɔːdiən ˈnɒt $ ˌɡɔːrdiən ˈnɑːt/ noun → cut/untie the Gordian knot
Examples from the Corpus
Gordian knot• Many of us have learned the legend of Alexander the Great and the Gordian Knot.• A similar attempt to cut the Gordian knot of Chapter 4 also proves to be fallacious.• Wine and women-here we have the Gordian knot of the crisis.• If Gorbachev expects to untie the Gordian knot, he has over-estimated his powers.Origin Gordian knot (1500-1600) From a complicated knot tied by Gordius, king of ancient Phrygia, which Alexander the Great cut through with his sword 