retrogress
verbUK /ˌretrəˈɡres/
US /ˌretrəˈɡres/
To go backward or become worse instead of better.
Without practice, his piano skills began to retrogress.
RELATED WORDS
OTHER MEANINGS
2. To return to an earlier, less advanced stage of development.
The species seemed to retrogress into a simpler form.
3. To move backward physically.
The glacier began to retrogress up the valley.
4. To decline in quality or condition over time.
The neighborhood's parks retrogressed after the budget cuts.