THE IDIOM COLLECTION LEARN & PRACTISE
A hard nut to crack
Understand the meaning. See it in context. Make it yours.
01 / UNDERSTAND
Meaning in plain English
A problem that is very difficult to solve, or a person who is difficult to understand.
02 / SEE IT IN CONTEXT
The expression in a sentence
- The final puzzle was a hard nut to crack.
03 / CHECK YOUR UNDERSTANDING
Quick idiom quiz
Try the question without looking back, then write a sentence of your own. You can retry as often as you like.
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Can you recall the expression?
Complete the example using the expression from this lesson.
The final puzzle was ________.
Show the answer
A hard nut to crack — A problem that is very difficult to solve, or a person who is difficult to understand.
Try your own sentence (optional)
Make it yours
Write one sentence using “A hard nut to crack” about your own life.
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Does your sentence match this meaning?
A problem that is very difficult to solve, or a person who is difficult to understand.
Compare: The final puzzle was a hard nut to crack.
Check the spelling and how the expression fits the sentence. Your example can be different.
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More ways to understand and use it
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When to use it
Use this conversational expression when describing a challenging puzzle or problem. When applied to a person it can sound judgemental, so describing the specific difficulty may be kinder.
More examples in context
- Finding a timetable that suited every group turned out to be a hard nut to crack.
- This coding error is a hard nut to crack, so we are checking one possibility at a time.
Usage note
A tough nut to crack is a variation. Keep a before hard or tough. The expression signals difficulty, not impossibility; a careful approach may still lead to a solution.
A short conversation
A: Have you solved the last clue?
B: Not yet. It is a hard nut to crack.
A: Let’s list what we know before guessing again.
One more practice question
What does calling a problem a hard nut to crack mean?
A. It is difficult to solve.
B. It is already completely solved.
Check your answer
A. The expression describes the challenge involved, not a completed solution.
Related lessons
Meaning and usage checked against Cambridge Dictionary. Explanations, examples and conversation are original.