descent vs sinking

descent and sinking both are nouns.

Word	Noun	Adjective	Verb	Adverb
descent	Yes	No	No	No
sinking	Yes	No	No	No

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

Other hyponyms of descent include drop, fall, lightening, set, cascade, shower, slide.

descent (noun)	sinking (noun)
the act of changing your location in a downward direction	a descent as through liquid (especially through water)
properties attributable to your ancestry	a slow fall or decline (as for lack of strength)
a movement downward	a feeling caused by uneasiness or apprehension
the hereditary derivation of an individual
a downward slope or bend
the kinship relation between an individual and the individual's progenitors