What do each of them mean exactly? Is either (or both) the opposite of "progress"?
Could someone please explain the difference?
To add some context:
When I look up the definitions I see the definition for regress is "to return to a previous, usually worse or less developed state", whereas the definition for retrogress is "to go back to an earlier, esp worse, condition".
They both look the same to me: antonyms of "progress".
But when I used the term "retrogress" at one point someone corrected me to use the word "regress", and I didn't understand what the difference is... so now I'm confused at how the two are different, and when to use which.