· the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale

Hypernym(s): consistency, consistence, substance, body

Antonym(s): softness

· a quality of water that contains dissolved mineral salts that prevent soap from lathering; "the costs of reducing hardness depend on the relative amounts of calcium and magnesium compounds that are present"

Hypernym(s): quality

· devoid of passion or feeling; hardheartedness

Synonym(s): unfeelingness, callousness, callosity, insensibility

Hypernym(s): insensitivity, insensitiveness

· the quality of being difficult to do; "he assigned a series of problems of increasing hardness"; "the ruggedness of his exams caused half the class to fail"

Synonym(s): ruggedness

Hypernym(s): difficulty, difficultness

· excessive sternness; "severity of character"; "the harshness of his punishment was inhuman"; "the rigors of boot camp"

Synonym(s): severity, severeness, harshness, rigor, rigour, rigorousness, rigourousness, inclemency, stiffness

Hypernym(s): sternness, strictness