compactness vs spacing

compactness and spacing both are nouns.

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

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

compactness: the spatial property of being crowded together
spacing: the property possessed by an array of things that have space between them

Other hypernyms of compactness include spatial arrangement.

compactness (noun)	spacing (noun)
the spatial property of being crowded together	the property possessed by an array of things that have space between them
the consistency of a compact solid	the time between occurrences of a repeating event