A tough nut to crack describes a problem, task, or person that is difficult to deal with, solve, or understand. Like a hard-shelled nut, it resists easy efforts and needs extra force, patience, or skill. Literal: a nut with a shell that is hard to break open. Figurative: a stubborn problem or person.
Origin & History
The image comes from cracking nuts: some shells split easily, but others are so hard that they resist a nutcracker and need real effort to open. A 'tough nut' became a natural symbol for anything stubbornly difficult.
The expression has been used in English since the 18th century, with related forms such as 'a hard nut to crack'. It is now common in everyday speech to describe demanding problems and also people who are reserved or hard to persuade.
Example Sentences
| Sentence | Context |
|---|---|
| The final exam question was a tough nut to crack. | Education, difficulty |
| Winning his trust was a tough nut to crack. | People, persuasion |
| This bug has been a tough nut to crack all week. | Technology, problem |
| Negotiating with that supplier is a tough nut to crack. | Business, negotiation |
How to Use It
The idiom is used as a noun phrase, usually after 'be': it's a tough nut to crack; he's a tough nut to crack. It is informal to neutral and works in speech and writing. It can describe a hard problem or a person who is difficult to win over, and the variant 'a hard nut to crack' has the same meaning.
Common Mistakes
Mistakes to Avoid
A tough nut to break.
A tough nut to crack. — The fixed verb is 'crack'.
A tough nuts to crack.
A tough nut to crack. — Keep 'nut' singular in the set phrase.
A rough nut to crack.
A tough nut to crack. — The adjective is 'tough', not 'rough'.
Similar Idioms
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