compactness vs density

compactness and density both are nouns.

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

As nouns, compactness and density are synonyms defined as:

Other synonyms of compactness include concentration, denseness, tightness.

As nouns, density is a hyponym of compactness; that is, density is a word with a more specific, narrower meaning than compactness:

Other hyponyms of compactness include denseness.

compactness (noun)	density (noun)
the spatial property of being crowded together	the amount per unit size
the consistency of a compact solid	the spatial property of being crowded together