| Answer | Crossword Clue |
|---|---|
| STEEL | Toughness of nerve |
| SINEW | Source of toughness |
| NAILS | Symbol of toughness |
| STEEL | Symbol of toughness |
| NAILS | Epitome of toughness |
| NAILS | Exemplar of toughness |
| NAILS | Exemplars of toughness |
| NAILS | Symbols of toughness |
| toughnesses | TOUGHNESS, the state of being tough |
| bulletwood | the wood of a tropical American sapotaceous tree, widely used for construction due to its durability and toughness |
| bulletwoods | BULLETWOOD, the wood of a tropical American sapotaceous tree, widely used for construction due to its durability and toughness |
