hardness

noun

1.
the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale
Antonym:
softness
Derived from:
hard
2.
a quality of water that contains dissolved mineral salts that prevent soap from lathering
3.
devoid of passion or feeling; hardheartedness
callosity callousness insensibility unfeelingness
Derived from:
hard
4.
the quality of being difficult to do
ruggedness
Derived from:
hard
5.