compactness vs solidness

compactness and solidness both are nouns.

Word	Noun	Adjective	Verb	Adverb
compactness	Yes	No	No	No
solidness	Yes	No	No	No

As nouns, solidness is a hypernym of compactness; that is, solidness is a word with a broader meaning than compactness:

Other hypernyms of compactness include solidity.

compactness (noun)	solidness (noun)
the spatial property of being crowded together	the quality of being substantial or having substance
the consistency of a compact solid	the quality of being solid and reliable financially or factually or morally
	the consistency of a solid
	the state in which a substance has no tendency to flow under moderate stress; resists forces (such as compression) that tend to deform it; and retains a definite size and shape