hard nut to crack

Idioms  

1. 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]

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Example Sentences

But he does stress that it’s a very hard nut to crack with limited upside.

From Los Angeles Times • Feb. 14, 2026

The $60 level proved a strong support and “is going to be a hard nut to crack now back to the upside,” he adds.

From The Wall Street Journal • Oct. 16, 2025

Voice control is a hard nut to crack.

From The Verge • Apr. 24, 2022

This is actually a hard nut to crack and is something that will take time and many great minds to solve.

From Salon • Mar. 17, 2019

If it’s for me, I’m a hard nut to crack; and I take it standing up.

From "Dracula" by Bram Stoker