retrogression vs reversal

retrogression and reversal both are nouns.

Word	Noun	Adjective	Verb	Adverb
retrogression	Yes	No	No	No
reversal	Yes	No	No	No

As nouns, reversal is a hypernym of retrogression; that is, reversal is a word with a broader meaning than retrogression:

retrogression (noun)	reversal (noun)
returning to a former state	a change from one state to the opposite state
passing from a more complex to a simpler biological form	the act of reversing the order or place of
	turning in the opposite direction
	a major change in attitude or principle or point of view
	a judgment by a higher court that the judgment of a lower court was incorrect and should be set aside
	a decision to reverse an earlier decision
	turning in an opposite direction or position
	an unfortunate happening that hinders or impedes; something that is thwarting or frustrating