slenderness vs leanness

slenderness and leanness both are nouns.

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

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

Other hypernyms of slenderness include spareness, thinness.

slenderness (noun)	leanness (noun)
the quality of being slight or inadequate	the property of having little body fat
the property of an attractively thin person	the quality of being meager
relatively small dimension through an object as opposed to its length or width