a hard nut to crack

a hard/tough nut to crack

a difficult problem to solve A company whose product has sold well in the States may find the European market a tougher nut to crack.

Name	Pronounced	Usage
Zlatan	-	Croatian, Serbian, Bosnian, Macedonian, Bulgarian, Slovene
Sutekh	-	Egyptian Mythology
Cynesige	-	Anglo-Saxon
ŠIwa	-	Slavic Mythology
Kwabena	-	Western African, Akan
Nandag	-	Scottish