"toughness" in the noun sense
1. stamina, staying power, toughness
enduring strength and energy
2. huskiness, ruggedness, toughness
the property of being big and strong
3. temper, toughness
the elasticity and hardness of a metal object its ability to absorb considerable energy before cracking
4. formidability, toughness
impressive difficulty
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License