1.Definition: 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"

Category: General

2.Definition: devoid of passion or feeling; hardheartedness

Related Noun(s):callosity, callousness, insensibility

Category: General

3.Definition: excessive sternness

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

Category: General

4.Definition: the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale

Category: General

5.Definition: 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"

Related Noun(s):ruggedness

Category: General