| Answer | Crossword Clue |
|---|---|
| CODED | Hard to crack |
| PECAN | Hard nut to crack |
| POSER | Hard nut to crack. |
| ENIGMA | Hard nut to crack |
| ENIGMAS | Hard nuts to crack |
| POSER | Hard nut to crack |
| ACORN | Hard nut to crack? |
| ACORN | Hard nut to crack |
| SAFES | They may be hard to crack |
| EASYJOB | Not a hard nut to crack |
| SAFE | A good one is hard to crack |
| TOFFEE | Candy cooked until it reaches the hard-crack stage |
