regression vs retroversion

regression and retroversion both are nouns.

Word	Noun	Adjective	Verb	Adverb
regression	Yes	No	No	No
retroversion	Yes	No	No	No

As nouns, regression and retroversion are synonyms defined as:

Other synonyms of regression include regress, retrogression, reversion.

regression (noun)	retroversion (noun)
returning to a former state	returning to a former state
the relation between selected values of x and observed values of y (from which the most probable value of y can be predicted for any value of x)	translation back into the original language
(psychiatry) a defense mechanism in which you flee from reality by assuming a more infantile state	a turning or tilting backward of an organ or body part
an abnormal state in which development has stopped prematurely