reversion vs retrogression

reversion and retrogression both are nouns.

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

As nouns, reversion and retrogression are synonyms defined as:

Other synonyms of reversion include regress, regression, retroversion.

reversion (noun)	retrogression (noun)
a failure to maintain a higher state	returning to a former state
turning in the opposite direction	passing from a more complex to a simpler biological form
returning to a former state
(genetics) a return to a normal phenotype (usually resulting from a second mutation)
a reappearance of an earlier characteristic
(law) an interest in an estate that reverts to the grantor (or his heirs) at the end of some period (e.g., the death of the grantee)