a Gordian knot

(formal)

a difficult problem

Usage notes: In an old story, King Gordius of Phrygia tied a complicated knot which no one could make loose, until Alexander the Great cut it with his sword.

Homelessness in the inner cities has become a real Gordian knot.

Common Names:

Name	Pronounced	Usage
Finola	-	Irish, Scottish
Eusebio	-	Spanish, Italian
Kahurangi	-	Maori
Atkin	['ætkin]
Ruben	RUY-bən (Dutch)	Swedish, Norwegian, Danish, Dutch, French, Armenian, Biblical Latin
Clancy	KLANT-see	Irish, English (Rare)