a hard nut to crack
Meaning
A difficult problem, person, or situation that is hard to understand, solve, or deal with.
Origin
From the literal image of a nut with a tough shell that resists cracking; by the 19th century it was used figuratively for difficult tasks or people.
Notes
Figurative and mildly informal. Implies persistence is needed. Used for problems or people; about people it can suggest they’re guarded or difficult to read.
Examples
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Getting our new printer to connect to the Wi‑Fi was a hard nut to crack, but we finally figured it out.
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The suspect is a hard nut to crack—he hasn’t revealed anything in hours of questioning.
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This calculus proof is a hard nut to crack; I’ve been stuck on it all afternoon.
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Winning over the board chair is a hard nut to crack, so we’ll need a strong proposal.
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Learning Japanese kanji can be a hard nut to crack at first, but practice helps a lot.
Grammar & Usage Notes
Typically used as a noun phrase with the article: “a hard nut to crack.” Can take modifiers (“a really hard nut to crack”). Often follows “be” (“X is a hard nut to crack”) or serves as a complement/object.
Synonyms
- a tough nut to crack
- a tricky problem
- a tough case
- a challenge
- an enigma
Antonyms
- a piece of cake
- easy to figure out
- straightforward