tough egg to crack

and tough nut to crack

n. a person or thing that is hard to figure out or hard to deal with. She won’t talk. She’s going to be a tough nut to crack! I wish Jill wasn’t such a tough nut to crack.

Common Names:

Name	Pronounced	Usage
Hariman	-	Ancient Germanic
Marta	MAHR-tah (Spanish, Italian, Polish, Czech)	Spanish, Italian, Portuguese, Catalan, Polish, Czech, Slovak, German, Dutch, Romanian, Slovene, Bulg
Hanley	['hænli]
Miska	MEES-kah (Finnish)	Hungarian, Finnish
Domenico	-	Italian
Shemer	-	Biblical