slenderness vs spareness

slenderness and spareness both are nouns.

Word	Noun	Adjective	Verb	Adverb
slenderness	Yes	No	No	No
spareness	Yes	No	No	No

As nouns, spareness is a hypernym of slenderness; that is, spareness is a word with a broader meaning than slenderness:

Other hypernyms of slenderness include leanness, thinness.

slenderness (noun)	spareness (noun)
the quality of being slight or inadequate	the property of being scanty or scattered; lacking denseness
the property of an attractively thin person	the property of having little body fat
relatively small dimension through an object as opposed to its length or width