tough nut

Idioms  

1. see hard nut to crack.

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Example Sentences

Getafe, seventh, often prove a tough nut to crack at home and they frustrated their neighbours.

From Barron's

If you've been introduced to Cat Burns through Celebrity Traitors, you might assume she's a tough nut to crack.

From BBC

That’s a very tough nut to crack.

From Los Angeles Times

While Chinese firms have expanded into East Asia and South America, for years the European market proved a tough nut to crack – that is, until governments here decided to phase out the sale of new petrol and diesel models.

From BBC

Combining consistent speed with the mental solidity and racing decisiveness he has always shown makes Piastri a formidable rival who, psychologically at least, will be a tough nut to crack.

From BBC