thickness vs soupiness

thickness and soupiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
thickness	Yes	No	No	No
soupiness	Yes	No	No	No

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

Other hyponyms of thickness include semifluidity, creaminess.

thickness (noun)	soupiness (noun)
the dimension through an object as opposed to its length or width	the property of having the thickness of heavy cream
resistance to flow	falsely emotional in a maudlin way
used of a line or mark
indistinct articulation