crunch vs hard nut to crack

crunch

noun
  • A problem that leads to a crisis. 

  • A form of abdominal exercise, based on a sit-up but in which the lower back remains in contact with the floor. 

  • A dessert consisting of a crunchy topping with fruit underneath. 

  • The overtime work required to catch up and finish a project, usually in the final weeks of development before release. 

  • A shortage. 

  • A critical moment or event. 

  • A small piece created by crushing; a piece of material with a friable or crunchy texture. 

  • A noisy crackling sound; the sound usually associated with crunching. 

  • The symbol #. 

verb
  • To emit a grinding or crunching noise. 

  • To calculate or otherwise process (e.g. to crunch numbers: to perform mathematical calculations). Presumably from the sound made by mechanical calculators. 

  • To make employees work overtime in order to meet a deadline in the development of a project. 

  • To be crushed with a noisy crackling sound. 

  • To cause the gears to emit a crunching sound by releasing the clutch before the gears are properly synchronised. 

  • To crush something, especially food, with a noisy crackling sound. 

  • To grind or press with violence and noise. 

  • To compress (data) using a particular algorithm, so that it can be restored by decrunching. 

hard nut to crack

noun
  • A problem that is challenging to solve. 

  • Used other than figuratively or idiomatically: see hard, nut, crack. 

  • A situation, person, group, etc. which is difficult to overcome or deal with. 

  • A place, opportunity, etc. to which it is difficult to gain entry. 

  • An amount that is difficult to finance. 

How often have the words crunch and hard nut to crack occurred in a corpus of books? (source: Google Ngram Viewer )