Meaning
A problem, task or person that is unusually difficult to solve, influence or get to know; 'a tough nut to crack' is an equally common variant. It applies to anything stubbornly resistant, from a puzzle or negotiation to a reserved newcomer. Informal to neutral and good-natured; no harsh judgement is implied about the person or problem described. Regional use: General English.
Origin
The metaphor is physical: a hard-shelled nut resists the teeth, so anything comparably stubborn becomes a nut that must be cracked. The earliest attestation recorded by the OED, as set out by the Bunny Trails word-history podcast, comes from 1570, in Thomas North's English translation of Anton Francesco Doni's The Moral Philosophy ('the hardest Nutte to crack'). Later landmarks include a 1659 London periodical describing a place as 'a hard Nut to crack', and Benjamin Franklin writing in 1745 that fortified towns 'are hard nuts to crack; and your teeth have not been accustomed to it'. The phrase flourished in nineteenth-century American newspapers, with 'tough nut to crack' rising to parity with 'hard' by the 1890s.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- a hard nut
- a nut to crack
- a tough nut to crack
- quite a tough nut
Usage Examples
- The cipher in the exhibition catalogue proved a hard nut to crack for three successive teams of students.
- Her grandfather was a tough nut to crack until the twins showed him their drawings.
- Persuading the utility to release the records was the hardest nut the newsroom had ever had to crack.