toughness

باللغة العربية: صَلَابَة، قَسْوَة، صُمُود

1. Resistance to fracture when stressed, or the degree of such resistance. (countable, uncountable)
2. Fortitude; hardiness; mettle. (countable, uncountable)
3. A formidable difficulty. (countable, uncountable)

الجمع toughnesses