slenderness vs insufficiency

slenderness and insufficiency both are nouns.

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

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

Other hypernyms of slenderness include deficiency, inadequacy.

slenderness (noun)	insufficiency (noun)
the quality of being slight or inadequate	lack of an adequate quantity or number
the property of an attractively thin person	(pathology) inability of a bodily part or organ to function normally
relatively small dimension through an object as opposed to its length or width	a lack of competence