downhill vs descent

downhill and descent both are nouns.

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

As nouns, descent is a hypernym of downhill; that is, descent is a word with a broader meaning than downhill:

Other hypernyms of downhill include declension, declination, decline, declivity, downslope, fall.

downhill (noun)	descent (noun)
a ski race down a trail	the act of changing your location in a downward direction
the downward slope of a hill	properties attributable to your ancestry
	a movement downward
	the hereditary derivation of an individual
	a downward slope or bend
	the kinship relation between an individual and the individual's progenitors

downhill (adjective)	descent (adjective)
sloping down rather steeply

downhill (adverb)	descent (adverb)
toward the bottom of a hill
toward a lower or inferior state