thinness vs gauntness

thinness and gauntness both are nouns.

Word	Noun	Adjective	Verb	Adverb
thinness	Yes	No	No	No
gauntness	Yes	No	No	No

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

thinness (noun)	gauntness (noun)
the property of having little body fat	extreme leanness (usually caused by starvation or disease)
relatively small dimension through an object as opposed to its length or width
a consistency of low viscosity
the property of being very narrow or thin
the property of being scanty or scattered; lacking denseness
The property of lacking substance or strength.