Hardness is a related term of compactness.
As nouns the difference between hardness and compactness
is that hardness is the quality of being hard while compactness is the state of being compact.
hardness
English
Noun
The quality of being hard.
An instance of this quality; hardship.
See also
* hardiness
References
*
compactness
English
Noun
(-)
the state of being compact