hard nut to crack

a hard nut (to crack)

A person, thing, situation, or problem that is particularly difficult to understand, solve, or deal with. I've been dating Jenny for over a year, and I still think she's a hard nut to crack! Figuring out the best way to modernize our product without alienating existing customers is definitely a hard nut to crack. The spy we captured is a hard nut; he hasn't said a thing since we began the interrogation.
See also: hard, nut

(a) hard nut to crack

 and (a) tough nut to crack
Fig. difficult person or problem to deal with. This problem is getting me down. It's a hard nut to crack. Tom sure is a hard nut to crack. I can't figure him out.
See also: crack, hard, nut

hard nut to crack

Also, tough nut to crack. A difficult problem; also, an individual who is difficult to deal with. For example, This assignment is a hard nut to crack, or It won't be easy getting her approval; she's a tough nut to crack. This metaphoric expression alludes to hard-shelled nuts like walnuts. [Early 1700s]
See also: crack, hard, nut
References in classic literature ?
If it's for me, I'm a hard nut to crack, and I take it standing up.
However, condensation can be a hard nut to crack and doing this doesn't work every time.
He said to smash network of the terrorists was a hard nut to crack but the Pak Army and other security forces succeeded in clearing hideouts of the terrorists.
The Gardens were well on top in this game - but found the Residents a hard nut to crack.
It is never easy to play Australia and especially at their own den, they are a hard nut to crack.
We tell them that their sadness and disappointment will last long as they will find Bahrainis' unity a hard nut to crack," the Premier said.
He said: "But I think Liverpool "is going to be a hard nut to crack.
Front-runner Special Tiara ran well below par when beaten at a short price at Ballinrobe on his last outing in August, but the former A Grade One winner is a hard nut to crack on his day.
Mr Clarkson added: "South Yorkshire is a hard nut to crack but I'll tell you what - Ukip are in there now and Labour have got to be looking over their shoulder at us.
A superb 8-3 11-3 win over Dutch champion Guurtje Copier saw her through to the final, where she found Lincoln's Brenda Barlow a hard nut to crack - but, after losing the second set, the Gwent ace dominated the tiebreak, and stormed home 9-5 4-7 2-0.
Morgans Pond was also a hard nut to crack for the good entry in the club's open match.
Maslany said that she is excited for the fans to get to know more of Rachel, as she is a "little bit of a hard nut to crack.
Muscat: Corruption in the energy sector is a hard nut to crack and gave no assurances that it would not happen again in the future, said Minister of Oil and Gas Dr Mohammed bin Hamad Al Rumhy on Monday.
Emma Thompson starts off as a hard nut to crack before smoothly morphing into a negotiator who must yield to the monster machine that is Hollywood because she needs money.
Port Talbot will be a hard nut to crack, having not lost in their last five matches.