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
Mercy	MUR-see	English
Matheus	-	Portuguese (Brazilian)
Anaxagoras	-	Ancient Greek
FernÃO	-	Portuguese
Vicki	VIK-ee	English
Rashid	-	Arabic