the state or quality of being hard
: the hardness of ice.
a relative degree or extent of this quality: wood of a desirable hardness.
that quality in water that is imparted by the presence of dissolved salts, especially calcium
sulfate or bicarbonate.
unfeelingness or jadedness; callousness.
harshness or austerity, as of a difficult existence.
6. South Midland U.S.
; bad feelings: There's a lot of hardness between those two boys.
the comparative ability of a substance to scratch or be scratched by another. Compare Mohs scale
Metallurgy. the measured resistance of a metal to indention, abrasion, deformation, or machining.
Origin: before 900; Middle English hardnes, Old English heardnes.